Author
Message
TAGS:
Manager

Joined: 17 Jul 2010

Posts: 123

Followers: 1

Kudos [? ]:
29
[1 ]
, given: 43

If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
23 Aug 2012, 19:45
1

This post received KUDOS

Question Stats:

75% (02:12) correct

25% (01:17) wrong

based on 421 sessions
If |10y - 4| > 7 and y < 1, which of the following could be y?

A. -0.8

B. -0.1

C. 0.1

D. 0

E. 1

Last edited by

Bunuel on 24 Aug 2012, 00:27, edited 2 times in total.

Renamed the topic and edited answer choices.

Retired Moderator

Status: 2000 posts! I don't know whether I should feel great or sad about it! LOL

Joined: 04 Oct 2009

Posts: 1720

Location: Peru

Schools: Harvard, Stanford, Wharton, MIT & HKS (Government)

WE 1: Economic research

WE 2: Banking

WE 3: Government: Foreign Trade and SMEs

Followers: 79

Kudos [? ]:
510
[1 ]
, given: 109

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
23 Aug 2012, 19:54
1

This post received KUDOS

Please, write well your question. It seems that choices C and E are the same.

_________________

"Life’s battle doesn’t always go to stronger or faster men; but sooner or later the man who wins is the one who thinks he can." My Integrated Reasoning Logbook / Diary: my-ir-logbook-diary-133264.html GMAT Club Premium Membership - big benefits and savings

Math Expert

Joined: 02 Sep 2009

Posts: 29108

Followers: 4725

Kudos [? ]:
49735
[4 ]
, given: 7403

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
24 Aug 2012, 00:39
4

This post received KUDOS

Intern

Joined: 16 Dec 2012

Posts: 4

Followers: 0

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

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
13 Feb 2013, 10:58

why cant we get an answer by simply substituting values in the equation |10y - 4| > 7

MBA Section Director

Affiliations: GMAT Club

Joined: 21 Feb 2012

Posts: 1930

Location: India

City: Pune

GPA: 3.4

WE: Business Development (Manufacturing)

Followers: 239

Kudos [? ]:
1649
[0 ] , given: 1293

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
13 Feb 2013, 11:31
mehasingh wrote:

why cant we get an answer by simply substituting values in the equation |10y - 4| > 7

In my opinion applying rules in modulus is much more easier than checking for multiple values.

The rules are simple.

1) !x! < a -------> -a < x < a

so if !x-a! < r then -r < x-a < r -------> a-r < x < a+r

2) !x! > a ------> either x > a or x < -a

so if !X-a! > r then either x-a > r ------> x > a+r

or x-a < -r -----> -x+a > r --------> x < a-r

Regards,

Abhijit

_________________

Live Q&A with B-School Adcoms - 2015 Season Be the coolest guy in the MBA Forum - Be a threadmaster! Have a blog? Feature it on GMAT Club !All MBA Resources All 'Sticky' Topics at one place Please share your profiles for this application season: 2015 Profiles w/ Admit/Dings Results! GMAT Club Premium Membership - big benefits and savings Next Generation GMATClub CATS with Brilliant Analytics.

Math Expert

Joined: 02 Sep 2009

Posts: 29108

Followers: 4725

Kudos [? ]:
49735
[0 ] , given: 7403

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
13 Feb 2013, 11:41

Intern

Joined: 14 Aug 2011

Posts: 7

Followers: 0

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

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
05 Jul 2013, 12:01

Bunuel wrote:

laythesmack23 wrote:

If |10y - 4| > 7 and y < 1, which of the following could be y? A. -0.8 B. -0.1 C. 0.1 D. 0 E. 1

We can simply plug answer choices less than 1 and see which one satisfies given inequality, or do the following:

\(|10y - 4| > 7\) means that either \(10y-4>7\) (when \(y>\frac{4}{10}\)) or \(-(10y-4)>7\) (when \(y\leq{\frac{4}{10}}\)).

Solve both inequalities:

\(10y-4>7\) --> \(y>1.1\). Since we are told that \(y<1\), then discard this solution.

\(-(10y-4)>7\) --> \(y<-0.3\). Only answer choice which is less than -0.3 is -0.8.

Answer: A.

Hope it's clear.

If I am not mistaken you have a typo in your explanation: 10y-4>7 shall be y>11/10 not y>4/10.

Math Expert

Joined: 02 Sep 2009

Posts: 29108

Followers: 4725

Kudos [? ]:
49735
[0 ] , given: 7403

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
05 Jul 2013, 12:10
rhallik wrote:

Bunuel wrote:

laythesmack23 wrote:

If |10y - 4| > 7 and y < 1, which of the following could be y? A. -0.8 B. -0.1 C. 0.1 D. 0 E. 1

We can simply plug answer choices less than 1 and see which one satisfies given inequality, or do the following:

\(|10y - 4| > 7\) means that either \(10y-4>7\) (when \(y>\frac{4}{10}\)) or \(-(10y-4)>7\) (when \(y\leq{\frac{4}{10}}\)).

Solve both inequalities:

\(10y-4>7\) --> \(y>1.1\). Since we are told that \(y<1\), then discard this solution.

\(-(10y-4)>7\) --> \(y<-0.3\). Only answer choice which is less than -0.3 is -0.8.

Answer: A.

Hope it's clear.

If I am not mistaken you have typos in your explanation: 10y-4>7 shall be y>11/10 not y>4/10. The same applies to -(10y-4)...

No typo there.

When \(y>\frac{4}{10}\), then we have \(10y-4>7\) --> \(y>11/10\).

When \(y\leq{\frac{4}{10}}\)), then we have \(-(10y-4)>7\) --> \(y<-3/10\).

Hope it's clear.

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!! PLEASE READ AND FOLLOW: 12 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 ; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) ; 12. 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 ? 25 extra-hard Quant Tests GMAT Club Premium Membership - big benefits and savings

Senior Manager

Joined: 13 May 2013

Posts: 475

Followers: 1

Kudos [? ]:
90
[0 ] , given: 134

Re: If |10y-4| > 7 and y < 1, which of the following could be y? [#permalink ]
09 Jul 2013, 15:14

If |10y - 4| > 7 and y < 1, which of the following could be y? |10y - 4| > 7 |10(-.8) - 4| > 7 |-8-4| > 7 |-12| > 7 |12| > 7 12 > 7 (A)

Intern

Joined: 29 Sep 2013

Posts: 19

GPA: 3.86

WE: Asset Management (Investment Banking)

Followers: 3

Kudos [? ]:
2
[0 ] , given: 6

I am going through the Algebra work book (MGMAT) and I am trying to figure out why the answer to question 5, in the Chapter 7 problem set is -.8. Here is the question If l10y-4l>7 & Y,1, which one of the following could be y? a.-.8 b. -.1 c. .1 d. 0 e. 1 I know how to solve the problem, I am just not sure how the answer is -.8 when the solution are: Y>11/10 or 1.1 & Y<-3/10 or -.3 I tried to combine the inequality but it didnt make sense, once I changed the signs to go in the same direction.

Math Expert

Joined: 02 Sep 2009

Posts: 29108

Followers: 4725

Kudos [? ]:
49735
[0 ] , given: 7403

Similar topics
Author
Replies
Last post
Similar Topics:

3
1. If x > 2 and y < -2, then which of the following must be true
surenz298
5
08 Dec 2014, 16:40

6
If x>y & 1/x<1/y, which of the following could be true
Game
1
20 Jul 2014, 17:36

3
If y>0>x, and (3+5y)/(x−1) < −7, then which of the following
bagdbmba
10
01 Jul 2013, 22:38

15
If |y-1/2| < 11/2, which of the following could be a value
Bunuel
20
06 Aug 2012, 01:49

6
If -4 < x < 7 and -6 < y < 3, which of the following specifies all the
pike
13
13 Jan 2011, 18:08