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

It is currently 25 Jul 2014, 10:33

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

Collection of 8 DS questions

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 22 Jan 2013
Posts: 1
Followers: 0

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

Re: Collection of 8 DS questions [#permalink] New post 23 Jan 2013, 07:43
Pls Help me.

In DS questions when it asks for .. IS some data followed by ? given 2 statement below.

A definite yes or definite no is sufficient for the answer. or when we should use this method ???
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18739
Followers: 3247

Kudos [?]: 22402 [0], given: 2619

Re: Collection of 8 DS questions [#permalink] New post 23 Jan 2013, 07:51
Expert's post
Jayalakshivit wrote:
Pls Help me.

In DS questions when it asks for .. IS some data followed by ? given 2 statement below.

A definite yes or definite no is sufficient for the answer. or when we should use this method ???


In a Yes/No Data Sufficiency questions, statement(s) is sufficient if the answer is “always yes” or “always no” while a statement(s) is insufficient if the answer is "sometimes yes" and "sometimes no".

When a DS question asks about the value of some variable, then the statement(s) is sufficient ONLY if you can get the single numerical value of this variable.


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

Senior Manager
Senior Manager
avatar
Joined: 17 Apr 2013
Posts: 498
Concentration: Entrepreneurship, Leadership
Schools: HBS '16
GMAT Date: 11-30-2013
GPA: 3.3
Followers: 1

Kudos [?]: 37 [0], given: 232

Re: Set of 8 DS questions [#permalink] New post 13 Jun 2013, 09:08
asterixmatrix wrote:
Bunuel wrote:

2. Is the measure of one of the interior angles of quadrilateral ABCD equal to 60?
(1) Two of the interior angles of ABCD are right angles.
(2) The degree measure of angle ABC is twice the degree measure of angle BCD.

Please share your way of thinking, not only post the answers.

OA and explanations to follow.


Option 1 we know 2 angles are 90 degree each but we have no info about the other 2 angles which can be (60,120), (80,100) etc. hence insuff
Option 2 says angle ABC = 2 * angle BCD again insuff as we can have an angle equal to 60 degree or none of the angles as 60degree

Taking 1 and 2 we know 2 angles are 90degree each and angle ABC is twice angle BCD
lets assume angle ABC = 90 degree then angle BCD = 45. we know the 3rd angle is 90 degree so 4th angle becomes 135 (sum of angles of a quadrilateral = 360degrees) so answer will NO ( none of angles are 60degree)
now lets consider that the 1st unknown angle is twice the 2nd unknown angle (other 2 are 90 degree each) we can get value for smaller angle as 60degree
hence insuff

will go with E


Asterix
from eeek?? to Eureka!!! to eeek???


One angle is x other is 2x, x+2x =180(360-180), this gives x = 60 degree....B is correct...
_________________

Like my post Send me a Kudos :) It is a Good manner.

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18739
Followers: 3247

Kudos [?]: 22402 [0], given: 2619

Re: Set of 8 DS questions [#permalink] New post 13 Jun 2013, 09:13
Expert's post
trafficspinners wrote:
asterixmatrix wrote:
Bunuel wrote:

2. Is the measure of one of the interior angles of quadrilateral ABCD equal to 60?
(1) Two of the interior angles of ABCD are right angles.
(2) The degree measure of angle ABC is twice the degree measure of angle BCD.

Please share your way of thinking, not only post the answers.

OA and explanations to follow.


Option 1 we know 2 angles are 90 degree each but we have no info about the other 2 angles which can be (60,120), (80,100) etc. hence insuff
Option 2 says angle ABC = 2 * angle BCD again insuff as we can have an angle equal to 60 degree or none of the angles as 60degree

Taking 1 and 2 we know 2 angles are 90degree each and angle ABC is twice angle BCD
lets assume angle ABC = 90 degree then angle BCD = 45. we know the 3rd angle is 90 degree so 4th angle becomes 135 (sum of angles of a quadrilateral = 360degrees) so answer will NO ( none of angles are 60degree)
now lets consider that the 1st unknown angle is twice the 2nd unknown angle (other 2 are 90 degree each) we can get value for smaller angle as 60degree
hence insuff

will go with E


Asterix
from eeek?? to Eureka!!! to eeek???


One angle is x other is 2x, x+2x =180(360-180), this gives x = 60 degree....B is correct...


OA's are given here: collection-of-8-ds-questions-85290.html#p639290 OA fot this question is E, not B.

Is the measure of one of the interior angles of quadrilateral ABCD equal to 60?

Sum of inner angels of quadrilateral is 360 degrees. (Sum of inner angles of polygon=180*(n-2), where n is # of sides)

(1) Two of the interior angles of ABCD are right angles --> angles can be 90+90 + any combination of two angels totaling 180. Not sufficient.

(2) The degree measure of angle ABC is twice the degree measure of angle BCD --> <ABC=2<BCD. Not sufficient

(1)+(2) Angles can be 90+90+45+135 Or 90+90+60+120. Not sufficient.

Answer: E.
_________________

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: 17 Apr 2013
Posts: 498
Concentration: Entrepreneurship, Leadership
Schools: HBS '16
GMAT Date: 11-30-2013
GPA: 3.3
Followers: 1

Kudos [?]: 37 [0], given: 232

Re: Set of 8 DS questions [#permalink] New post 13 Jun 2013, 09:23
By combining both we can get answer.

Two of the interior angles of ABCD are right angles. which sum of two interior angles = 180

Now fom B

The degree measure of angle ABC is twice the degree measure of angle BCD. i.e. 1:2,

X+2X + 90 + 90 = 360
3X=180
X=60
_________________

Like my post Send me a Kudos :) It is a Good manner.

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18739
Followers: 3247

Kudos [?]: 22402 [0], given: 2619

Re: Set of 8 DS questions [#permalink] New post 13 Jun 2013, 09:26
Expert's post
trafficspinners wrote:
By combining both we can get answer.

Two of the interior angles of ABCD are right angles. which sum of two interior angles = 180

Now fom B

The degree measure of angle ABC is twice the degree measure of angle BCD. i.e. 1:2,

X+2X + 90 + 90 = 360
3X=180
X=60


Again OA is E, not C. Check the solution above: Angles can be 90+90+45+135 Or 90+90+60+120. Not sufficient.
_________________

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: 25 Jan 2014
Posts: 41
Concentration: Strategy, International Business
GMAT 1: 600 Q44 V29
GMAT 2: 710 Q48 V38
GPA: 3.35
WE: Analyst (Computer Software)
Followers: 0

Kudos [?]: 10 [0], given: 4

Re: Collection of 8 DS questions [#permalink] New post 15 May 2014, 04:01
Bunuel, thanks for the wonderful set, i had a question

. Is x^4 + y^4 > z^4 ?
(1) x^2 + y^2 > z^2
(2) x+y > z

x^4 + y^4 = ((x^2) + (y^2))^2 - 2*x^2*y^2

So basically we want to find out if ((x^2) + (y^2))^2 - 2*x^2*y^2 > z^4

OR if

((x^2) + (y^2))^2 > z^4 + 2*x^2*y^2

Now by (1), we know that x^2 + y^2 > z^2

Or

((x^2) + (y^2))^2 > z^4 ( squaring both sides, both sides are absolutely positive)...... (a)

We also know that 2*x^2*y^2 will be less than ((x^2) + (y^2))^2......(b)

Combining (a) and (b), can we not conclude that ((x^2) + (y^2))^2 > z^4 + 2*x^2*y^2 and hence making (1) sufficient
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18739
Followers: 3247

Kudos [?]: 22402 [0], given: 2619

Re: Collection of 8 DS questions [#permalink] New post 15 May 2014, 05:41
Expert's post
gaurav1418z wrote:
Bunuel, thanks for the wonderful set, i had a question

. Is x^4 + y^4 > z^4 ?
(1) x^2 + y^2 > z^2
(2) x+y > z

x^4 + y^4 = ((x^2) + (y^2))^2 - 2*x^2*y^2

So basically we want to find out if ((x^2) + (y^2))^2 - 2*x^2*y^2 > z^4

OR if

((x^2) + (y^2))^2 > z^4 + 2*x^2*y^2

Now by (1), we know that x^2 + y^2 > z^2

Or

((x^2) + (y^2))^2 > z^4 ( squaring both sides, both sides are absolutely positive)...... (a)

We also know that 2*x^2*y^2 will be less than ((x^2) + (y^2))^2......(b)

Combining (a) and (b), can we not conclude that ((x^2) + (y^2))^2 > z^4 + 2*x^2*y^2 and hence making (1) sufficient


Is x^4+y^4>z^4?

The best way to deal with this problem is plugging numbers. Remember on DS questions when plugging numbers, goal is to prove that the statement is not sufficient. So we should try to get a YES answer with one chosen number(s) and a NO with another.

(1) x^2+y^2>z^2
It's clear that we get YES answer very easily with big x and y (say 10 and 10), and small z (say 0).

For NO answer let's try numbers from Pythagorean triples:
x^2=3, y^2=4 and z^2=5 (x^2+y^2=7>5=z^2) --> x^4+y^4=9+16=25=z^4, so we have answer NO (x^4+y^4 is NOT more than z^4, it's equal to it).

Not sufficient.

(2) x+y>z. This one is even easier: again we can get YES answer with big x and y, and small z.

As for NO try to make z some big enough negative number: so if x=y=1 and z=-5, then x^4+y^4=1+1=2<25=z^4.

Not sufficient.

(1)+(2) As we concluded YES answer is easily achievable. For NO try the case of x^2=3, y^2=4 and z^2=5 again: x+y=\sqrt{3}+\sqrt{4}>\sqrt{5} (\sqrt{3}+2 is more than 3 and \sqrt{5} is less than 3), so statement (2) is satisfied, we know that statement (1) is also satisfied (x^2+y^2=7>5=z^2) and x^4+y^4=9+16=25=z^4. Not sufficient.

Answer: E.

OPEN DISCUSSION OF THIS QUESTION IS HERE: is-x-4-y-4-z-101358.html
_________________

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: 25 Jan 2014
Posts: 41
Concentration: Strategy, International Business
GMAT 1: 600 Q44 V29
GMAT 2: 710 Q48 V38
GPA: 3.35
WE: Analyst (Computer Software)
Followers: 0

Kudos [?]: 10 [0], given: 4

Re: Collection of 8 DS questions [#permalink] New post 15 May 2014, 05:57
Ok Bunuel, i shall stick to the plugging number approach, please can you confirm if both terms in an equality are positive, we can square both sides or even raise to the power of 3, without changing the inequality sign?
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18739
Followers: 3247

Kudos [?]: 22402 [0], given: 2619

Re: Collection of 8 DS questions [#permalink] New post 15 May 2014, 06:10
Expert's post
gaurav1418z wrote:
Ok Bunuel, i shall stick to the plugging number approach, please can you confirm if both terms in an equality are positive, we can square both sides or even raise to the power of 3, without changing the inequality sign?


1. We can raise both parts of an inequality to an even power if we know that both parts of an inequality are non-negative (the same for taking an even root of both sides of an inequality)

2. We can always raise both parts of an inequality to an odd power (the same for taking an odd root of both sides of an inequality).


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

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: 30 Mar 2013
Posts: 1
Followers: 0

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

Re: Collection of 8 DS questions [#permalink] New post 22 Jun 2014, 14:56
asterixmatrix wrote:
Bunuel wrote:
1. An integer greater than 1 that is not prime is called composite. If the two-digit integer n is greater than 20, is n composite?
(1) The tens digit of n is a factor of the units digit of n.
(2) The tens digit of n is 2.



Please share your way of thinking, not only post the answers.

OA and explanations to follow.


given n >20. let N be of the form 10x + y where x is ten's digit and y is units digit

1. x is a factor of y. Lets assume x = 2,3 or 4 then y can have values 2,4,6,8,9 . All possible combinations will give a composite number . hence suff
2. we do not have any info about units digit so insuff
hence A



Answer is C. X can also be 1. 1 is factor of all the numbers.
Re: Collection of 8 DS questions   [#permalink] 22 Jun 2014, 14:56
    Similar topics Author Replies Last post
Similar
Topics:
571 Experts publish their posts in the topic Valuable Collection of Percentage Questions (PS/DS) MBAhereIcome 33 03 Sep 2011, 05:45
130 Experts publish their posts in the topic Extreme collection of 2000 DS and PS Questions: Download MisterEko 37 12 Dec 2010, 18:37
1 Still in progress! Sharing collection of DS questions posted AtifS 4 18 Mar 2010, 12:36
29 Experts publish their posts in the topic Collection of 12 DS questions Bunuel 78 17 Oct 2009, 17:45
Collection of DS questions peergmatclub 1 07 Jun 2008, 16:36
Display posts from previous: Sort by

Collection of 8 DS questions

  Question banks Downloads My Bookmarks Reviews Important topics  

Go to page   Previous    1   2   3   [ 51 posts ] 



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®.