BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
Live EA class + 6 months of EA OnDemand
  • Expert-led weekly online sessions
  • EA Masterclass access between classes
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

130-point score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

If -2 < a < 11 and 3 < b < 12, then which of the

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 2560
Joined: Sun Oct 29, 2017 2:04 pmFollowed by: 6 members
by swerve » Sat Nov 25, 2017 8:06 am
$$If\ \ -2 < a < 11$$ and $$3 < b < 12$$
Then which of the following is NOT always true?

$$A.\ \ 1 < a + b < 23$$
$$B.\ \ -14 < a - b < 8$$
$$C.\ \ -7 < b - a < 14$$
$$D.\ \ 1 < b + a < 23$$
$$E.\ \ -24 < a*b < 132$$

The OA is C.

Please, can any expert explain this PS question for me? I have many difficulties to understand why that is the correct answer. Thanks.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Wed Nov 29, 2017 8:35 am
swerve wrote:$$If\ \ -2 < a < 11$$ and $$3 < b < 12$$
Then which of the following is NOT always true?

$$A.\ \ 1 < a + b < 23$$
$$B.\ \ -14 < a - b < 8$$
$$C.\ \ -7 < b - a < 14$$
$$D.\ \ 1 < b + a < 23$$
$$E.\ \ -24 < a*b < 132$$

The OA is C.

Please, can any expert explain this PS question for me? I have many difficulties to understand why that is the correct answer. Thanks.
If we can find values for a and b that CONTRADICT one of the answer choices, then that answer choice will be correct.

Answer choice C: -7 < b - a < 14
From the given information, b COULD equal 3.1 and a COULD equal 10. 9
In this case, b - a = 3.1 - 10.9 = -7.8
HOWEVER, answer choice C says that b - a is GREATER than -7 (which it is not)

So, the correct answer must be C

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8177
Joined: Sat Apr 25, 2015 10:56 amFollowed by: 29 members
Location: Los Angeles, CA
Thanked: 43 times

by Scott@TargetTestPrep » Sat Oct 12, 2019 3:54 pm
swerve wrote:$$If\ \ -2 < a < 11$$ and $$3 < b < 12$$
Then which of the following is NOT always true?

$$A.\ \ 1 < a + b < 23$$
$$B.\ \ -14 < a - b < 8$$
$$C.\ \ -7 < b - a < 14$$
$$D.\ \ 1 < b + a < 23$$
$$E.\ \ -24 < a*b < 132$$

The OA is C.

Please, can any expert explain this PS question for me? I have many difficulties to understand why that is the correct answer. Thanks.
The values of (b - a) range from 3 - 11 = -8 to 12 - (-2) = 14. That is, -8 < b - a < 14. Since (b - a) could be, for example, -7.5, we see that the inequality in choice C is not always true.

Answer: C

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1