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

 It is currently 19 Sep 2018, 22:05

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

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

If S^2 > T^2 , which of the following must be true?

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 49258
If S^2 > T^2 , which of the following must be true?  [#permalink]

Show Tags

19 Jul 2018, 01:43
00:00

Difficulty:

15% (low)

Question Stats:

77% (00:42) correct 23% (00:51) wrong based on 57 sessions

HideShow timer Statistics

If S^2 > T^2 , which of the following must be true?

(A) S > T

(B) S^2 > T

(C) ST > 0

(D) |S| > |T|

(E) ST < 0

_________________
examPAL Representative
Joined: 07 Dec 2017
Posts: 592
If S^2 > T^2 , which of the following must be true?  [#permalink]

Show Tags

Updated on: 19 Jul 2018, 04:05
1
Bunuel wrote:
If S^2 > T^2 , which of the following must be true?

(A) S > T

(B) S^2 > T

(C) ST > 0

(D) |S| > |T|

(E) ST < 0

As all we're given are equations, we'll work with them.
This is a Precise approach.

Simplifying our given data gives S^2 - T^2 > 0 --> (S - T)(S + T) > 0

So both S - T and S + T are positive in which case both S and T must be positive and S > T.
Or both S - T and S + T are negative in which case both S and T must be negative and S < T.

Looking at our answer choices, (A), (C), (E) are all directly contradicted by one of the above options.
(D) works because if both S and T are positive then S > T --> |S| > |T| and if both are negative then S < T means that S has a larger absolute value.
(B) can fail for some fractional values (such as T = 0.5 and S = 0.6 so S > T but S^2 < T)

_________________

Watch free GMAT tutorials in Math, Verbal, IR, and AWA.

GMAT test takers: Watch now the GMAC interview with the people who write the GMAT test!
We discussed the chances of improving a GMAT score; how important the first questions on the test are; what to do if you don’t have enough time to complete a whole section; and more.

You can watch all the action from the interview here.

Originally posted by DavidTutorexamPAL on 19 Jul 2018, 01:49.
Last edited by DavidTutorexamPAL on 19 Jul 2018, 04:05, edited 1 time in total.
SC Moderator
Joined: 30 Jan 2015
Posts: 596
Location: India
Concentration: Operations, Marketing
GPA: 3.5
Re: If S^2 > T^2 , which of the following must be true?  [#permalink]

Show Tags

19 Jul 2018, 02:41
Bunuel wrote:
If S^2 > T^2 , which of the following must be true?

(A) S > T --> Incorrect, fails if S is -ve and T is +ve
(B) S^2 > T --> Incorrect, fails in case of fractions
(C) ST > 0 --> Incorrect, fails in case of opposite sign
(D) |S| > |T| --> Correct, means exactly the same, absolute value of a number = squared value of the number
(E) ST < 0 --> Incorrect, fails in case both S and T have same sign

Hence, D.
_________________

The few, the fearless !

Thanks

e-GMAT Representative
Joined: 04 Jan 2015
Posts: 1994
Re: If S^2 > T^2 , which of the following must be true?  [#permalink]

Show Tags

19 Jul 2018, 05:05

Solution

Given:
• S^2 > T^2

To find:
• Among the given option, which one is correct.

Approach and Working:

• $$S^2 > T^2$$
o It only means that Absolute value of S is greater than T.
 For example: $$3^2>2^2$$ and if you see|3|>|2| and |-3| >|-2|
o Thus, |s|> |T|

Hence, the correct answer is option D.

_________________

Number Properties | Algebra |Quant Workshop

Success Stories
Guillermo's Success Story | Carrie's Success Story

Ace GMAT quant
Articles and Question to reach Q51 | Question of the week

Number Properties – Even Odd | LCM GCD | Statistics-1 | Statistics-2
Word Problems – Percentage 1 | Percentage 2 | Time and Work 1 | Time and Work 2 | Time, Speed and Distance 1 | Time, Speed and Distance 2
Advanced Topics- Permutation and Combination 1 | Permutation and Combination 2 | Permutation and Combination 3 | Probability
Geometry- Triangles 1 | Triangles 2 | Triangles 3 | Common Mistakes in Geometry
Algebra- Wavy line | Inequalities

Practice Questions
Number Properties 1 | Number Properties 2 | Algebra 1 | Geometry | Prime Numbers | Absolute value equations | Sets

| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

Director
Joined: 31 Oct 2013
Posts: 571
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
If S^2 > T^2 , which of the following must be true?  [#permalink]

Show Tags

19 Jul 2018, 13:52
Bunuel wrote:
If S^2 > T^2 , which of the following must be true?

(A) S > T

(B) S^2 > T

(C) ST > 0

(D) |S| > |T|

(E) ST < 0

Note: Squared value and absolute value are alike.

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3518
Location: United States (CA)
Re: If S^2 > T^2 , which of the following must be true?  [#permalink]

Show Tags

22 Jul 2018, 18:30
Bunuel wrote:
If S^2 > T^2 , which of the following must be true?

(A) S > T

(B) S^2 > T

(C) ST > 0

(D) |S| > |T|

(E) ST < 0

Taking the square root of both sides, we have:

|S| > |T|

Note: If you are wondering why B is not true, take S = 2/5 and T = 1/5.

_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Re: If S^2 > T^2 , which of the following must be true? &nbs [#permalink] 22 Jul 2018, 18:30
Display posts from previous: Sort by

Events & Promotions

 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®.