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

It is currently 16 Jul 2018, 01:36

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

If 0 < st < 1 then which of the following can be true?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 47010
If 0 < st < 1 then which of the following can be true? [#permalink]

Show Tags

New post 17 May 2018, 05:01
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

60% (01:16) correct 40% (01:28) wrong based on 91 sessions

HideShow timer Statistics

If \(0 < st < 1\), then which of the following can be true?


(A) s < -1 and t > 0

(B) s < -1 and t < — 1

(C) s > - 1 and t < - 1

(D) s > 1 and t < —1

(E) s > 1 and t > 1

_________________

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

Expert Post
Top Contributor
1 KUDOS received
CEO
CEO
User avatar
P
Joined: 12 Sep 2015
Posts: 2630
Location: Canada
Re: If 0 < st < 1 then which of the following can be true? [#permalink]

Show Tags

New post 17 May 2018, 08:08
1
Top Contributor
Bunuel wrote:
If \(0 < st < 1\), then which of the following can be true?


(A) s < -1 and t > 0

(B) s < -1 and t < -1

(C) s > - 1 and t < -1

(D) s > 1 and t < -1

(E) s > 1 and t > 1


Let's examine each answer choice.....

(A) s < -1 and t > 0
This tells us that s is NEGATIVE and t is POSITIVE, which means the product st must be NEGATIVE
We're told that 0 < st < 1, which means st is POSITIVE
Eliminate answer choice A

(B) s < -1 and t < -1
This tells us that s is NEGATIVE and t is NEGATIVE , which means the product st must be POSITIVE
We're told that 0 < st < 1, which means st is POSITIVE (so far good!)
However, if s < -1 and t < -1, the product st will be GREATER THAN 1, and we're told that st is LESS THAN 1
Eliminate answer choice B

(C) s > - 1 and t < -1
So, it COULD be the case that s = -0.5 and t = -1.2, in which case st = (-0.5)(-1.2) = 0.6
Perfect! [since it is true that 0 < 0.6 < 1]

Answer: C

Cheers,
Brent
_________________

Brent Hanneson – Founder of gmatprepnow.com

Image

Manager
Manager
avatar
G
Joined: 28 Jul 2016
Posts: 135
Premium Member
Re: If 0 < st < 1 then which of the following can be true? [#permalink]

Show Tags

New post 07 Jul 2018, 11:16
1
If 0<st<10<st<1, then which of the following can be true?


(A) s < -1 and t > 0 --- s*t = negative, so eliminate
(B) s < -1 and t < — 1 --- st > 1, so eliminate
(C) s > - 1 and t < - 1 , looks good, s = -0,2; t = -2, so s*t = +0,4
(D) s > 1 and t < —1 --- s*t = negative, so eliminate
(E) s > 1 and t > 1 --- st > 1, so eliminate
Senior Manager
Senior Manager
User avatar
G
Joined: 14 Dec 2017
Posts: 369
Re: If 0 < st < 1 then which of the following can be true? [#permalink]

Show Tags

New post 07 Jul 2018, 11:50
Bunuel wrote:
If \(0 < st < 1\), then which of the following can be true?


(A) s < -1 and t > 0

(B) s < -1 and t < — 1

(C) s > - 1 and t < - 1

(D) s > 1 and t < —1

(E) s > 1 and t > 1


Given 0 < st < 1,

we have s*t > 0, so s & t both have the same sign

s*t < 1, so either s or t or both are between 0 & 1 or both are between -1 & 0

(A) s < -1 and t > 0 gives opposite signs to s & t, hence not possible. s = -2 , t = 1 , s*t = - 2 < 0

(B) s < -1 and t < — 1 both are less than -1, hence not possible. s = -2, t = -1.5, s*t = 3 > 1

(C) s > - 1 and t < - 1 both can be of same sign & s can be more than -1 but less than 0. Possible. s = -0.5, t = - 1.2, s*t = 0.6 < 1

(D) s > 1 and t < —1 gives opposite signs to s & t, hence not possible. s = 2, t = -2, s*t = -4 < 0

(E) s > 1 and t > 1 both are more than 1, hence not possible. s = 1.2, t = 1.2, s*t = 1.44 > 1


Answer C.



Thanks,
GyM
Expert Post
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6202
Re: If 0 < st < 1 then which of the following can be true? [#permalink]

Show Tags

New post 07 Jul 2018, 12:05
Bunuel wrote:
If \(0 < st < 1\), then which of the following can be true?


(A) s < -1 and t > 0

(B) s < -1 and t < — 1

(C) s > - 1 and t < - 1

(D) s > 1 and t < —1

(E) s > 1 and t > 1



TIP
0<st<1..... So atleast one of s or t should be a fraction between -1 and 1..
Both have to be of same sign to give it's product as positive..
Remember it is CAN be true

Eliminate A as s is negative and t is positive, so st<0

In remaining , only C gives s>-1, so possibility of it to be a fraction
S can be -1/4 and t can be -2, st=1/2

C
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Re: If 0 < st < 1 then which of the following can be true?   [#permalink] 07 Jul 2018, 12:05
Display posts from previous: Sort by

If 0 < st < 1 then which of the following can be true?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Events & Promotions

PREV
NEXT


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®.