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

 It is currently 22 Feb 2019, 19:34

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

Events & Promotions

Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• Free GMAT RC Webinar

February 23, 2019

February 23, 2019

07:00 AM PST

09:00 AM PST

Learn reading strategies that can help even non-voracious reader to master GMAT RC. Saturday, February 23rd at 7 AM PT
• FREE Quant Workshop by e-GMAT!

February 24, 2019

February 24, 2019

07:00 AM PST

09:00 AM PST

Get personalized insights on how to achieve your Target Quant Score.

If a is less than b, which of the following numbers is greater than a

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

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 53066
If a is less than b, which of the following numbers is greater than a  [#permalink]

Show Tags

26 Oct 2017, 23:18
00:00

Difficulty:

5% (low)

Question Stats:

84% (01:05) correct 16% (01:42) wrong based on 63 sessions

HideShow timer Statistics

If a is less than b, which of the following numbers is greater than a and less than b ?

(A) (a + b)/2
(B) ab/2
(C) b^2 – a^2
(D) ab
(E) b – a

_________________
Retired Moderator
Joined: 25 Feb 2013
Posts: 1217
Location: India
GPA: 3.82
If a is less than b, which of the following numbers is greater than a  [#permalink]

Show Tags

27 Oct 2017, 01:19
Bunuel wrote:
If a is less than b, which of the following numbers is greater than a and less than b ?

(A) (a + b)/2
(B) ab/2
(C) b^2 – a^2
(D) ab
(E) b – a

given $$b>a$$. we need to find $$x$$ where $$a<x<b$$

(A) $$\frac{(a + b)}{2}$$ ----this is the mid-point of $$a$$ & $$b$$ in a number line. Hence has to be between $$a$$ & $$b$$. Correct

(B) $$\frac{ab}{2}$$ ------ if $$a=2$$ & $$b = 4$$, then $$\frac{ab}{2}=b$$. Does not satisfy the condition

(C) $$b^2 – a^2$$--------- again if $$a=1$$ and $$b=4$$, then $$b^2-a^2=15>b$$. Does not satisfy the condition

(D) $$ab$$ ------ if $$a=2$$ & $$b = 4$$, then $$ab=8>b$$. Does not satisfy the condition

(E) $$b – a$$ ------if $$a=-1$$ and $$b=1$$, then $$b-a=2>b$$. Does not satisfy the condition

Option A
Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2827
Re: If a is less than b, which of the following numbers is greater than a  [#permalink]

Show Tags

30 Oct 2017, 13:08
Bunuel wrote:
If a is less than b, which of the following numbers is greater than a and less than b ?

(A) (a + b)/2
(B) ab/2
(C) b^2 – a^2
(D) ab
(E) b – a

Let’s take a = 3 and b = 4 and test each answer choice:

A) (a + b)/2 = (3 + 4)/2 = 3.5

We see that (a + b)/2 is greater than a and less than b.

We could stop here, but let’s double-check the remaining answer choices.

B) ab/2 = 3(4)/2 = 6

We see that ab is greater than b.

C) b^2 - a^2 = 16 - 9 = 7

We see that b^2 - a^2 is greater than b.

D) ab = 3(4) = 12

We see that ab is greater than b.

E) b - a = 4 - 3 = 1

We see that b - a is less than a.

The only answer choice that produced a value between a and b is A.

_________________

Jeffery Miller
Head of GMAT Instruction

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

Manager
Status: Gathering chakra
Joined: 05 Feb 2018
Posts: 65
Re: If a is less than b, which of the following numbers is greater than a  [#permalink]

Show Tags

06 Feb 2019, 07:14
Bunuel wrote:
If a is less than b, which of the following numbers is greater than a and less than b ?

(A) (a + b)/2
(B) ab/2
(C) b^2 – a^2
(D) ab
(E) b – a

Testing choices, a=4, b=5
A) 9/2 = 4.5, looks good
B) 20/2 = 10, not <b
C) 25-16=9, not <b
D) 20, not <b
E) 5-4 = 1, not >a

Thinking about it logically, adding a+b together and then dividing by two means the number will be halfway between a and b, so regardless of what value we pick it will be <b and >a.
Re: If a is less than b, which of the following numbers is greater than a   [#permalink] 06 Feb 2019, 07:14
Display posts from previous: Sort by

If a is less than b, which of the following numbers is greater than a

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

 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®.