GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 12 Dec 2018, 04:00

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.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • The winning strategy for 700+ on the GMAT

     December 13, 2018

     December 13, 2018

     08:00 AM PST

     09:00 AM PST

    What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.
  • GMATbuster's Weekly GMAT Quant Quiz, Tomorrow, Saturday at 9 AM PST

     December 14, 2018

     December 14, 2018

     09:00 AM PST

     10:00 AM PST

    10 Questions will be posted on the forum and we will post a reply in this Topic with a link to each question. There are prizes for the winners.

An investment of d dollars at k percent simple annual interest yields

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Intern
Intern
avatar
Joined: 24 Apr 2010
Posts: 26
An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 04 May 2010, 02:24
1
7
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

81% (01:24) correct 19% (01:49) wrong based on 247 sessions

HideShow timer Statistics

An investment of d dollars at k percent simple annual interest yields $600 over a 2 year period. In terms of d, what dollar amount invested at the same rate will yield $2,400 over a 3 year period?

A. (2d)/3
B. (3d)/4
C. (4d)/3
D. (3d)/2
E. (8d)/3

OPEN DISCUSSION OF THIS QUESTION IS HERE: an-investment-of-d-dollars-at-k-percent-simple-annual-106083.html
Manager
Manager
avatar
Joined: 24 Jul 2009
Posts: 244
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 04 May 2010, 02:42
perseverant wrote:
An investment of d dollars at k percent simple annual interes yields $600 interest over a 2 year period. In terms of d, what dollar amount invested at the same rate would yield $2400 of interest over a 3 year period?

a)(2d)/3
b)(3d)/4
c)(4d)/3
d)(3d)/2
e)(8d)/3

This is a question I got wrong in my GMATPrep test. Could someone help me get to the right answer?

Thanks!


IMHO E

case 1:

600 = (d * k * 2)/100
so, d*k = 30000 .............................(1)

Case 2:

Let the amount invested be "a"

so, 2400 = (a * k * 3)/100
a*k = 80000 .............................(2)

From (1) insert the value of k in (2)

a*(3000)/d = 80000
a = (8*d)/3
Intern
Intern
avatar
Joined: 09 Jan 2010
Posts: 27
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 04 May 2010, 02:47
hi perseverant,

first the prob states that

(P*N*R)/100 = I

(d*2*k)/100 = 600

d*k = 600 *50

Now try Substituting the answer choices since this is a variable in answer choice question such that the interest comes to 2400 $

Lets try option e

In this case P= 8d/3

N = 3

R = k (same rate)

I = (8d/3 * 3* k) /100 = (8*d*k)/100

But d*k = 600*50

substitute above we get

8*600*50 /100 = 8*600*1/2 = 4*600 = 2400

Therfore the answer is E.

whts the OA ??
Intern
Intern
avatar
Joined: 24 Apr 2010
Posts: 26
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 04 May 2010, 03:03
Thank you guys, you both are correct, the OA is e.
I tried to use the simple interest rate formula P*(1+r.t) since it's the only one I knew, but you both have used
I= (P*N*R)/100. I guess Im not very clear on why simple interest rate formula would not be the right one to start off.
Manager
Manager
avatar
Joined: 12 Jan 2010
Posts: 245
Schools: DukeTuck,Kelogg,Darden
Reviews Badge
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 04 May 2010, 06:05
4
1
perseverant wrote:
An investment of d dollars at k percent simple annual interes yields $600 interest over a 2 year period. In terms of d, what dollar amount invested at the same rate would yield $2400 of interest over a 3 year period?

a)(2d)/3
b)(3d)/4
c)(4d)/3
d)(3d)/2
e)(8d)/3

This is a question I got wrong in my GMATPrep test. Could someone help me get to the right answer?

Thanks!


Hi its E, here is how i did it

Currently the investment pays $600 in 2 years = $300/year

what we need is $2400 in 3 years = $800 a year

So the investment needs to be = 800/300 times the current investment = 8d/3.
_________________

Run towards the things that make you uncomfortable daily. The greatest risk is not taking risks
http://gmatclub.com/forum/from-690-to-730-q50-v38-97356.html

Intern
Intern
avatar
Joined: 24 Apr 2010
Posts: 26
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 04 May 2010, 10:23
Nice! I guess I didnt need to know any formula :)
Intern
Intern
avatar
Joined: 29 Jun 2011
Posts: 25
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 27 Aug 2011, 06:23
perseverant wrote:
An investment of d dollars at k percent simple annual interes yields $600 interest over a 2 year period. In terms of d, what dollar amount invested at the same rate would yield $2400 of interest over a 3 year period?

a)(2d)/3
b)(3d)/4
c)(4d)/3
d)(3d)/2
e)(8d)/3

This is a question I got wrong in my GMATPrep test. Could someone help me get to the right answer?

Thanks!


I got E but I'm not sure if my calculation is correct...quite weird. can anyone pls enlighten? thanks!

My way:
Case 1: d * k/100 * 2 = 600 (for 2 years period)
Case 2: d * k/100 * 3 = 2400 (for 3 years period)

So 2kd / 100 = 600 versus 3kd / 100 = 2400
=> 2kd = 60000 : 3kd = 240000
=> 2kd/60000 = 3kd/240000
=> 180000kd = 480000kd
=>3/8 kd
=> k = (8/3)d
Retired Moderator
avatar
Joined: 20 Dec 2010
Posts: 1820
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 27 Aug 2011, 06:33
miweekend wrote:
perseverant wrote:
An investment of d dollars at k percent simple annual interes yields $600 interest over a 2 year period. In terms of d, what dollar amount invested at the same rate would yield $2400 of interest over a 3 year period?

a)(2d)/3
b)(3d)/4
c)(4d)/3
d)(3d)/2
e)(8d)/3

This is a question I got wrong in my GMATPrep test. Could someone help me get to the right answer?

Thanks!


I got E but I'm not sure if my calculation is correct...quite weird. can anyone pls enlighten? thanks!

My way:
Case 1: d * k/100 * 2 = 600 (for 2 years period)
Case 2: d * k/100 * 3 = 2400 (for 3 years period)

So 2kd / 100 = 600 versus 3kd / 100 = 2400
=> 2kd = 60000 : 3kd = 240000
=> 2kd/60000 = 3kd/240000
=> 180000kd = 480000kd
=>3/8 kd
=> k = (8/3)d


I see that you got the answer right. I'd rather do it this way:

\(d*\frac{k}{100}*2=600\)
\(k=\frac{30000}{d}\)---------------------1

We got our rate in terms of d; let the new principal be x; now, we take the other case:
\(x*\frac{k}{100}*3=2400\)
\(x=\frac{80000}{k}\)

Write k in terms of d;
\(x=\frac{80000d}{30000}=\frac{8d}{3}\)

Ans: "E"
_________________

~fluke

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
avatar
Joined: 14 Mar 2011
Posts: 67
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 27 Aug 2011, 07:03
Most of Us got the Right answer, My Answer is also E, please find explanation below

we know that Principle*No. of Years* rate of interest= Interest

d*2*k/100 = 600 we get K=30000/d

Now we know the interest rate k & interest=2400 but amount is not know let it be x, nos. of years 3

x *3*k/100 = 2400
xk=800*100

put the value of K we get

x*30000/d=800*100
so x = 8/3*d
Director
Director
avatar
Joined: 01 Feb 2011
Posts: 659
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 27 Aug 2011, 08:36
Simple Interest = PRT

First Amount = d => P=d
Rate of interest = k/100
time T = 2

=> d*(k/100)(2) = 600 => k = 3*10^4/d


Second Amount

Rate of interest = k/100
time = 3
=> P (k/100)(3) = 2400

=> P(3*10^2/d)*3 = 2400

=> P = 8d/3

Answer is E.
Director
Director
User avatar
Joined: 03 May 2007
Posts: 800
Schools: University of Chicago, Wharton School
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 27 Aug 2011, 18:40
perseverant wrote:
An investment of d dollars at k percent simple annual interes yields $600 interest over a 2 year period. In terms of d, what dollar amount invested at the same rate would yield $2400 of interest over a 3 year period?

a)(2d)/3
b)(3d)/4
c)(4d)/3
d)(3d)/2
e)(8d)/3

This is a question I got wrong in my GMATPrep test. Could someone help me get to the right answer?


2dk = 600

Lets make the interest part 2400.

3dk = 2400
2dk (1.5) m = 600 x 4
2dk (m) = 600 x 4/(1.5)
2dk (m) = 600 x 8/3

m = 8/3 i.e. the amount in terms of d is = 8d/3
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51123
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 02 Jan 2015, 04:08
perseverant wrote:
An investment of d dollars at k percent simple annual interest yields $600 over a 2 year period. In terms of d, what dollar amount invested at the same rate will yield $2,400 over a 3 year period?

A. (2d)/3
B. (3d)/4
C. (4d)/3
D. (3d)/2
E. (8d)/3


Simple interest = principal * interest rate * time, where "principal" is the starting amount and "rate" is the interest rate at which the money grows per a given period of time (note: express the rate as a decimal in the formula). Time must be expressed in the same units used for time in the Rate.

An investment of d dollars at k percent simple annual interest yields $600 over a 2 year period --> \(d*\frac{k}{100}*2=600\) --> \(k=\frac{30,000}{d}\)

What (x) dollar amount invested at the same rate will yield $2,400 over a 3 year period --> \(x*\frac{k}{100}*3=2,400\) --> \(x*\frac{30,000}{100d}*3=2,400\) --> \(x=\frac{8d}{3}\).

Answer: E.

Or another way: In order interest to be 4 times more in 1.5 times longer time period then investment must be 4d/1.5=8d/3.

Answer: E.

OPEN DISCUSSION OF THIS QUESTION IS HERE: an-investment-of-d-dollars-at-k-percent-simple-annual-106083.html
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

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?
Extra-hard Quant Tests with Brilliant Analytics

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 9130
Premium Member
Re: An investment of d dollars at k percent simple annual interest yields  [#permalink]

Show Tags

New post 11 Aug 2018, 07:33
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

GMAT Club Bot
Re: An investment of d dollars at k percent simple annual interest yields &nbs [#permalink] 11 Aug 2018, 07:33
Display posts from previous: Sort by

An investment of d dollars at k percent simple annual interest yields

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

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

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.