Find all School-related info fast with the new School-Specific MBA Forum

It is currently 22 Oct 2014, 04:49

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Samantha invests i1 dollars in bond X, which pays r1

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 08 Nov 2009
Posts: 16
Followers: 0

Kudos [?]: 1 [0], given: 0

Samantha invests i1 dollars in bond X, which pays r1 [#permalink] New post 02 Oct 2010, 10:56
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

57% (02:18) correct 43% (01:21) wrong based on 121 sessions
Samantha invests i1 dollars in bond X, which pays r1 percent simple interest annually, and she invests i2 dollars in bond Y, which pays r2 percent simple interest annually. After one year, will she have earned more interest, in dollars, from bond X than from bond Y ?

(1) (r1)^2 > (r2)^2
(2) The ratio of i1 to i2 is larger than the ratio of r1 to r2 .


[Reveal] Spoiler:
Why cant 1 be sufficient .
We know that interest cannot be negative , therefore (1) eventually leads to r1> r2 .
The values of i1 and I2 don’t matter , because even when i2 is greater than i1 , the interest would be less .Eg. i1 : 100 r1: 5% , i2: 150 , r2: 3% , i1r1 > i2r2 giving the required result .
[Reveal] Spoiler: OA

Last edited by nandini11 on 02 Oct 2010, 12:41, edited 1 time in total.
Intern
Intern
avatar
Status: yet to apply
Joined: 05 Jun 2010
Posts: 17
Followers: 0

Kudos [?]: 5 [0], given: 10

GMAT ToolKit User
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 11:11
nandini11 wrote:
Samantha invests i1 dollars in bond X , which pays r1 percent simple interest annually, and she invests i2 dollars in bond Y , which pays r2 percent simple interest annually. After one year, will she have earned more interest, in dollars, from bond X than from bond Y ?
1. (r1)^2 > (r2)^2
2. The ratio of i1 to i2 is larger than the ratio of r1 to r2 .


Why cant 1 be sufficient .
We know that interest cannot be negative , therefore (1) eventually leads to r1> r2 .
The values of i1 and I2 don’t matter , because even when i2 is greater than i1 , the interest would be less .Eg. i1 : 100 r1: 5% , i2: 150 , r2: 3% , i1r1 > i2r2 giving the required result .

OA

Well..i think the answer is E. Because in bonds the interest can be -ve and a variable one.
CEO
CEO
User avatar
Status: Nothing comes easy: neither do I want.
Joined: 12 Oct 2009
Posts: 2794
Location: Malaysia
Concentration: Technology, Entrepreneurship
Schools: ISB '15 (M)
GMAT 1: 670 Q49 V31
GMAT 2: 710 Q50 V35
Followers: 182

Kudos [?]: 986 [0], given: 235

Reviews Badge
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 11:18
First of all recheck the OA - it is C not E. Pls do not mislead people by posting wrong OA.
_________________

Fight for your dreams :For all those who fear from Verbal- lets give it a fight

Money Saved is the Money Earned :)

Jo Bole So Nihaal , Sat Shri Akaal

:thanks Support GMAT Club by putting a GMAT Club badge on your blog/Facebook :thanks

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Gmat test review :
670-to-710-a-long-journey-without-destination-still-happy-141642.html

Retired Moderator
User avatar
Joined: 02 Sep 2010
Posts: 807
Location: London
Followers: 76

Kudos [?]: 505 [0], given: 25

GMAT ToolKit User Reviews Badge
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 11:33
nandini11 wrote:
Samantha invests i1 dollars in bond X , which pays r1 percent simple interest annually, and she invests i2 dollars in bond Y , which pays r2 percent simple interest annually. After one year, will she have earned more interest, in dollars, from bond X than from bond Y ?
1. (r1)^2 > (r2)^2
2. The ratio of i1 to i2 is larger than the ratio of r1 to r2 .


Why cant 1 be sufficient .
We know that interest cannot be negative , therefore (1) eventually leads to r1> r2 .
The values of i1 and I2 don’t matter , because even when i2 is greater than i1 , the interest would be less .Eg. i1 : 100 r1: 5% , i2: 150 , r2: 3% , i1r1 > i2r2 giving the required result .

OA


Interest from bond X : i1*r1/100
Interest from bond Y : i2*r2/100
we need to know if i1*r1 > i2*r2 ?

(1) r1^2 > r2^2 ... Not sufficient as it doesn't tell us anything about the actual amounts invested
(2) i1/i2 > r1/r2 which implies i1*r2 > i2*r1 ... doesnt help us solve our inequality
(1+2) r1^2 > r2^2
So r1 > r2 as interest rate on bond cannot be negative
i1*r1 > i1*r2
i2*r1 > i2*r2
Combining with condition known from Statement 2, we get i1*r1 > i2*r2

Answer is (C)

sibanmishra wrote:
Well..i think the answer is E. Because in bonds the interest can be -ve and a variable one.


Bonds can't have negative interest. Variable is irrelevant here as we are given it is fixed
_________________

Math write-ups
1) Algebra-101 2) Sequences 3) Set combinatorics 4) 3-D geometry

My GMAT story

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Status: yet to apply
Joined: 05 Jun 2010
Posts: 17
Followers: 0

Kudos [?]: 5 [0], given: 10

GMAT ToolKit User
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 11:46
gurpreetsingh wrote:
First of all recheck the OA - it is C not E. Pls do not mislead people by posting wrong OA.


Sorry about that. i have not been through OG quant. So dint have any idea about the answer. I thought its E, cos i know that bond rates can be -ve when it's in loss. If you don't consider this fact, then the answer becomes C.
So, i think it is assumed that the interest is always positive.M i right??
CEO
CEO
User avatar
Status: Nothing comes easy: neither do I want.
Joined: 12 Oct 2009
Posts: 2794
Location: Malaysia
Concentration: Technology, Entrepreneurship
Schools: ISB '15 (M)
GMAT 1: 670 Q49 V31
GMAT 2: 710 Q50 V35
Followers: 182

Kudos [?]: 986 [0], given: 235

Reviews Badge
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 12:03
sibanmishra wrote:
gurpreetsingh wrote:
First of all recheck the OA - it is C not E. Pls do not mislead people by posting wrong OA.


Sorry about that. i have not been through OG quant. So dint have any idea about the answer. I thought its E, cos i know that bond rates can be -ve when it's in loss. If you don't consider this fact, then the answer becomes C.
So, i think it is assumed that the interest is always positive.M i right??


My post was for 'nandini11'.
_________________

Fight for your dreams :For all those who fear from Verbal- lets give it a fight

Money Saved is the Money Earned :)

Jo Bole So Nihaal , Sat Shri Akaal

:thanks Support GMAT Club by putting a GMAT Club badge on your blog/Facebook :thanks

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Gmat test review :
670-to-710-a-long-journey-without-destination-still-happy-141642.html

Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23369
Followers: 3607

Kudos [?]: 28758 [1] , given: 2846

Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 12:24
1
This post received
KUDOS
Expert's post
nandini11 wrote:
Samantha invests i1 dollars in bond X , which pays r1 percent simple interest annually, and she invests i2 dollars in bond Y , which pays r2 percent simple interest annually. After one year, will she have earned more interest, in dollars, from bond X than from bond Y ?
1. (r1)^2 > (r2)^2
2. The ratio of i1 to i2 is larger than the ratio of r1 to r2 .


Why cant 1 be sufficient .
We know that interest cannot be negative , therefore (1) eventually leads to r1> r2 .
The values of i1 and I2 don’t matter , because even when i2 is greater than i1 , the interest would be less .Eg. i1 : 100 r1: 5% , i2: 150 , r2: 3% , i1r1 > i2r2 giving the required result .

OA


First of all: "bond X pays r1 percent simple interest annually" --> so r1 and r2 can not be negative.

After 1 year bond X will earn i_1*\frac{r_1}{100} and bond Y i_2*\frac{r_2}{100}.

So the question is i_1*\frac{r_1}{100}>i_2*\frac{r_2}{100}? --> is i_1*r_1>i_2*r_2?

(1) (r_1)^2>(r_2)^2 --> not sufficient as no info about i_1 and i_2.
(2) The ratio of i1 to i2 is larger than the ratio of r1 to r2 --> \frac{i_1}{i_2}>\frac{r_1}{r_2} --> i_1*r_2>i_2*r_1. Not sufficient.

(1)+(2) From (1) (r_1)^2>(r_2)^2 --> r_1>r_2 --> \frac{r_1}{r_2}>1 --> so \frac{i_1}{i_2}>\frac{r_1}{r_2}>1 --> \frac{i_1}{i_2}>1 --> i_1>i_2. So as both r_1>r_2 and i_1>i_2 then i_1*r_1>i_2*r_2. Sufficient.

Or: as both part in both inequalities ((r_1)^2>(r_2)^2 and i_1*r_2>i_2*r_1) are positive then we can multiply them: (r_1)^2*i_1*r_2>(r_2)^2*i_2*r_1 --> reduce by r_1r_2 --> i_1*r_1>i_2*r_2. Sufficient.

Answer: C.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Status: yet to apply
Joined: 05 Jun 2010
Posts: 17
Followers: 0

Kudos [?]: 5 [0], given: 10

GMAT ToolKit User
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 12:26
Well..No one till now commented on the possibility of negative interest rate??
CEO
CEO
User avatar
Status: Nothing comes easy: neither do I want.
Joined: 12 Oct 2009
Posts: 2794
Location: Malaysia
Concentration: Technology, Entrepreneurship
Schools: ISB '15 (M)
GMAT 1: 670 Q49 V31
GMAT 2: 710 Q50 V35
Followers: 182

Kudos [?]: 986 [0], given: 235

Reviews Badge
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 12:33
sibanmishra wrote:
Well..No one till now commented on the possibility of negative interest rate??


-ve interest rates are not possible for such investment. Do not over generalize the things on gmat.
_________________

Fight for your dreams :For all those who fear from Verbal- lets give it a fight

Money Saved is the Money Earned :)

Jo Bole So Nihaal , Sat Shri Akaal

:thanks Support GMAT Club by putting a GMAT Club badge on your blog/Facebook :thanks

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Gmat test review :
670-to-710-a-long-journey-without-destination-still-happy-141642.html

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23369
Followers: 3607

Kudos [?]: 28758 [0], given: 2846

Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 12:33
Expert's post
sibanmishra wrote:
Well..No one till now commented on the possibility of negative interest rate??


There are comments on this in two posts above: we are told that "bond X pays r1 percent simple interest annually" so it can't be negative.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 08 Nov 2009
Posts: 16
Followers: 0

Kudos [?]: 1 [0], given: 0

Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 12:52
Hello Bunuel , Shrouded1 ,
What abt the following consideration .
from (1) we know r1 > r2 so irrespective of i1 being greater or less than i2 , we would know that i1*r1 yields high value .
Example
Consider i1 > i2 (and we know r1 >r2 and i1 and i2 have to be positive values ).
say i1 : 150 , i2 : 100
Value of Inv on X : i1*r1 : 150*5% : 7.5
Value of Inv on Y : i2*r2 : 100*3% : 3
Therefore X > Y
Take the other case of i1< i2 ( and still r1 >r2 and i1 and i2 have to be positive values ).
Say i1 : 100 , i2 : 150
Value of Inv on X : i1*r1 : 100*5% : 5
Value of Inv on Y : i2*r2 : 150*3% : 4.5
So it does not matter what is the principle amount hence (A) or stmnt 1 is sufficient .
Where am I going wrong ?

PS : Gurpreet I have corrected the OA .Sorry abt that .
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23369
Followers: 3607

Kudos [?]: 28758 [0], given: 2846

Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 13:05
Expert's post
nandini11 wrote:
Hello Bunuel , Shrouded1 ,
What abt the following consideration .
from (1) we know r1 > r2 so irrespective of i1 being greater or less than i2 , we would know that i1*r1 yields high value .
Example
Consider i1 > i2 (and we know r1 >r2 and i1 and i2 have to be positive values ).
say i1 : 150 , i2 : 100
Value of Inv on X : i1*r1 : 150*5% : 7.5
Value of Inv on Y : i2*r2 : 100*3% : 3
Therefore X > Y
Take the other case of i1< i2 ( and still r1 >r2 and i1 and i2 have to be positive values ).
Say i1 : 100 , i2 : 150
Value of Inv on X : i1*r1 : 100*5% : 5
Value of Inv on Y : i2*r2 : 150*3% : 4.5
So it does not matter what is the principle amount hence (A) or stmnt 1 is sufficient .
Where am I going wrong ?

PS : Gurpreet I have corrected the OA .Sorry abt that .


That's not correct. Are you saying that interest earned depends only on interest rate?

So if I ask you what would you prefer 1% annual interest from $1,000,000,000 or 100% annual interest from $1?
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Senior Manager
Senior Manager
avatar
Joined: 06 Jun 2009
Posts: 333
Location: USA
WE 1: Engineering
Followers: 1

Kudos [?]: 56 [0], given: 0

Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 13:31
Quote:
That's not correct. Are you saying that interest earned depends only on interest rate?

So if I ask you what would you prefer 1% annual interest from $1,000,000,000 or 100% annual interest from $1?


Bunuel, I will be more than happy to accept the former with only 0.25% :lol:
_________________

All things are possible to those who believe.

Intern
Intern
avatar
Joined: 08 Nov 2009
Posts: 16
Followers: 0

Kudos [?]: 1 [0], given: 0

Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 13:32
I get it now .My choice of plugin numbers was not comprehensive enuf .
Thanks a lot Bunuel .
Senior Manager
Senior Manager
avatar
Joined: 06 Jun 2009
Posts: 333
Location: USA
WE 1: Engineering
Followers: 1

Kudos [?]: 56 [0], given: 0

Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 02 Oct 2010, 13:38
nandini11 wrote:
Hello Bunuel , Shrouded1 ,
What abt the following consideration .
from (1) we know r1 > r2 so irrespective of i1 being greater or less than i2 , we would know that i1*r1 yields high value .
Example
Consider i1 > i2 (and we know r1 >r2 and i1 and i2 have to be positive values ).
say i1 : 150 , i2 : 100
Value of Inv on X : i1*r1 : 150*5% : 7.5
Value of Inv on Y : i2*r2 : 100*3% : 3
Therefore X > Y
Take the other case of i1< i2 ( and still r1 >r2 and i1 and i2 have to be positive values ).
Say i1 : 100 , i2 : 150
Value of Inv on X : i1*r1 : 100*5% : 5
Value of Inv on Y : i2*r2 : 150*3% : 4.5
So it does not matter what is the principle amount hence (A) or stmnt 1 is sufficient .
Where am I going wrong ?

PS : Gurpreet I have corrected the OA .Sorry abt that .


Nandini, the numbers you have taken in this particular case are playing the trick. In your example, the ratio of the R's and I's are peculiar.

Take extreme example. If you think i1 & i2 do not matter. Do this:

Case 1
i1=$10000 and i2=$100
r1=5% and r2=4.99% .. as a result r1>r2
Value of return ......... X = 10000*5% = $500
Y = 100*4.99% = $4.99
X >> Y

Case 2
i1=$100 and i2=$10000
r1=5% and r2=4.99% .. as a result r1>r2
Value of return ......... X = 100*5% = $5
Y = 10000*4.99% = $499
X << Y
_________________

All things are possible to those who believe.

Intern
Intern
avatar
Joined: 30 Jun 2013
Posts: 18
Followers: 1

Kudos [?]: 24 [0], given: 11

Premium Member
Re: GMAT Club Test -MGMAT Challenge Test 1- DS Question(#5) [#permalink] New post 11 Nov 2013, 12:59
Bunuel wrote:
nandini11 wrote:
Samantha invests i1 dollars in bond X , which pays r1 percent simple interest annually, and she invests i2 dollars in bond Y , which pays r2 percent simple interest annually. After one year, will she have earned more interest, in dollars, from bond X than from bond Y ?
1. (r1)^2 > (r2)^2
2. The ratio of i1 to i2 is larger than the ratio of r1 to r2 .


Why cant 1 be sufficient .
We know that interest cannot be negative , therefore (1) eventually leads to r1> r2 .
The values of i1 and I2 don’t matter , because even when i2 is greater than i1 , the interest would be less .Eg. i1 : 100 r1: 5% , i2: 150 , r2: 3% , i1r1 > i2r2 giving the required result .

OA


First of all: "bond X pays r1 percent simple interest annually" --> so r1 and r2 can not be negative.

After 1 year bond X will earn i_1*\frac{r_1}{100} and bond Y i_2*\frac{r_2}{100}.

So the question is i_1*\frac{r_1}{100}>i_2*\frac{r_2}{100}? --> is i_1*r_1>i_2*r_2?

(1) (r_1)^2>(r_2)^2 --> not sufficient as no info about i_1 and i_2.
(2) The ratio of i1 to i2 is larger than the ratio of r1 to r2 --> \frac{i_1}{i_2}>\frac{r_1}{r_2} --> i_1*r_2>i_2*r_1. Not sufficient.

(1)+(2) From (1) (r_1)^2>(r_2)^2 --> r_1>r_2 --> \frac{r_1}{r_2}>1 --> so \frac{i_1}{i_2}>\frac{r_1}{r_2}>1 --> \frac{i_1}{i_2}>1 --> i_1>i_2. So as both r_1>r_2 and i_1>i_2 then i_1*r_1>i_2*r_2. Sufficient.

Or: as both part in both inequalities ((r_1)^2>(r_2)^2 and i_1*r_2>i_2*r_1) are positive then we can multiply them: (r_1)^2*i_1*r_2>(r_2)^2*i_2*r_1 --> reduce by r_1r_2 --> i_1*r_1>i_2*r_2. Sufficient.

Answer: C.


Bunuel: Can you please explain -
(2) The ratio of i1 to i2 is larger than the ratio of r1 to r2 --> \frac{i_1}{i_2}>\frac{r_1}{r_2} --> i_1*r_2>i_2*r_1. Not sufficient.

I am not able to prove this as Not Sufficient.

Thanks.
Intern
Intern
avatar
Joined: 10 Dec 2013
Posts: 19
Location: India
Concentration: Technology, Strategy
Schools: ISB '16 (S)
GMAT 1: 710 Q48 V38
GPA: 3.9
WE: Consulting (Consulting)
Followers: 0

Kudos [?]: 6 [0], given: 7

Re: Samantha invests i1 dollars in bond X, which pays r1 [#permalink] New post 01 Mar 2014, 13:03
Can the rates R1 and R2 be fractions? In that case R1^2 > R2^2 would not necessarily mean R1>R2. :shock:
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23369
Followers: 3607

Kudos [?]: 28758 [0], given: 2846

Re: Samantha invests i1 dollars in bond X, which pays r1 [#permalink] New post 02 Mar 2014, 03:26
Expert's post
Rohan_Kanungo wrote:
Can the rates R1 and R2 be fractions? In that case R1^2 > R2^2 would not necessarily mean R1>R2. :shock:


Actually it would.

For non-negative x and y if x^2>y^2, then x>y: since both sides of x^2>y^2 are non-negative we can take the square root from both sides and get x>y.

Adding/subtracting/multiplying/dividing inequalities: help-with-add-subtract-mult-divid-multiple-inequalities-155290.html



Hope it helps.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

SVP
SVP
User avatar
Joined: 06 Sep 2013
Posts: 1738
Location: United States
Concentration: Finance
GMAT 1: 710 Q48 V39
WE: Corporate Finance (Investment Banking)
Followers: 14

Kudos [?]: 191 [0], given: 295

GMAT ToolKit User
Re: Samantha invests i1 dollars in bond X, which pays r1 [#permalink] New post 29 Mar 2014, 08:06
Is i1r1>i2r2?

Statement 1

ri>r2

This is clearly insufficient

Statement 2

i1/i2>r1/r2

i1r2>r1i2.

Insufficient on its own

Now both together

i1r2>r1i2
r1>r2

Multiplying inequalities since we know both sides are positive then simplifying we get

i2>i2

Since we know that r1>r2 as well then

i1r1>i2r2

Sufficient

C

Hope this helps
Cheers
J
Verbal Forum Moderator
Verbal Forum Moderator
User avatar
Status: Tomorrow will be a new day...
Joined: 22 Mar 2013
Posts: 943
Location: India
GPA: 3.51
WE: Information Technology (Computer Software)
Followers: 41

Kudos [?]: 411 [0], given: 209

Re: Samantha invests i1 dollars in bond X, which pays r1 [#permalink] New post 14 Apr 2014, 08:48
Read to eat stuff: it will refresh your concept and keep you away from any confusion during exam.
Kudos me if it is helpful.
Attachment:
Ratio properties.jpg
Ratio properties.jpg [ 81.01 KiB | Viewed 369 times ]

_________________

Piyush K
-----------------------
Our greatest weakness lies in giving up. The most certain way to succeed is to try just one more time. ― Thomas A. Edison
Don't forget to press--> Kudos :)
My Articles: 1. WOULD: when to use? | 2. All GMATPrep RCs (New)
Tip: Before exam a week earlier don't forget to exhaust all gmatprep problems specially for "sentence correction".

Re: Samantha invests i1 dollars in bond X, which pays r1   [#permalink] 14 Apr 2014, 08:48
    Similar topics Author Replies Last post
Similar
Topics:
5 Experts publish their posts in the topic Samantha's investment portfolio consists of three stocks joylive 4 24 Nov 2012, 08:15
1 Experts publish their posts in the topic A certain sum was invested in a high-interest bond for which punyadeep 10 16 Mar 2011, 06:49
If $4500 dollars was invested in a bond fund when the price tinman1412 5 23 Jul 2007, 17:40
A certain sum was invested in a high-interest bond for which ywilfred 5 25 Mar 2005, 01:28
Person A invests x dollars and B invests y dollars. A earns pb_india 4 06 Jan 2005, 09:45
Display posts from previous: Sort by

Samantha invests i1 dollars in bond X, which pays r1

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.