It is currently 24 Feb 2018, 15:44

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 June
Open Detailed Calendar

If a, b, and c are integers and a*b^2/c is a positive even

Author Message
TAGS:

Hide Tags

Manager
Joined: 25 Jul 2010
Posts: 139
If a, b, and c are integers and a*b^2/c is a positive even [#permalink]

Show Tags

26 Sep 2010, 12:04
1
KUDOS
16
This post was
BOOKMARKED
00:00

Difficulty:

45% (medium)

Question Stats:

60% (01:00) correct 40% (01:10) wrong based on 698 sessions

HideShow timer Statistics

If a, b, and c are integers and a*b^2/c is a positive even integer, which of the following must be true?

I. ab is even
II. ab > 0
III. c is even

A. I only
B. II only
C. I and II
D. I and III
E. I, II, and III
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 43898

Show Tags

26 Sep 2010, 12:43
5
KUDOS
Expert's post
8
This post was
BOOKMARKED
Orange08 wrote:
If a , b, and c are integers and $$a*b^2/c$$is a positive even integer, which of the following must
be true?

I. ab is even
II. ab > 0
III. c is even

I only
II only
I and II
I and III
I, II, and III

Given: $$\frac{a*b^2}{c}=even>0$$ --> $$ab^2=c*even=even$$ --> either $$a$$ is even or $$b$$ or both.

I. $$ab$$ is even --> according to the above this must be true;

II. $$ab>0$$ --> not necessarily true, $$b$$ could be positive as well as negative (for example $$a=1$$, $$c=1$$ and $$b=-2$$);

III. $$c$$ is even --> not necessarily true, see above example.

_________________
Intern
Joined: 30 Mar 2010
Posts: 8

Show Tags

28 Sep 2010, 06:22
Two ways this can happen: 1- Even/ Even= Even or 2- Even/Odd= Even
So Ab MUST be even, with either A or B being even, Ab does not have to be positive, as B could be negative and once it is raised to 2 it becomes positive again, and of course, C could be Odd or Even as described above.

I only.letter A
Manager
Joined: 18 Oct 2016
Posts: 139
Location: India
WE: Engineering (Energy and Utilities)
Re: If a, b, and c are integers and a*b^2/c is a positive even [#permalink]

Show Tags

18 Apr 2017, 01:27
Option A

(a*(b^2))/c = Positive Even integer. Odd: O, Even: E & fraction: F.
i.e., a,b,c are Even or b is even, a & c are Odd or a is Even, b & c are odd.

I. ab is even : True
II. ab > 0 : May or May NOT be True. no information about b's value.
III. c is even : May or May not be True
_________________

Press Kudos if you liked the post!

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2192
Location: United States (CA)
Re: If a, b, and c are integers and a*b^2/c is a positive even [#permalink]

Show Tags

20 Apr 2017, 15:43
Orange08 wrote:
If a, b, and c are integers and a*b^2/c is a positive even integer, which of the following must be true?

I. ab is even
II. ab > 0
III. c is even

A. I only
B. II only
C. I and II
D. I and III
E. I, II, and III

We are given that (a*b^2)/c is a positive even integer. Therefore, a*b^2 must be even. (If a*b^2 is odd, (a*b^2)/c can’t ever be even.)

Now recall that the product of an even number and any integer is even, so either a or b, or both, must be even. Thus we see that ab must be an even integer. However, ab DOES NOT have to be greater than zero, since a could be -2 and b could be 1. Finally, we see that c does not have to be even, since a could be -2, b could be 1, and c = -1. Thus, only Roman numeral I must be true.

_________________

Scott Woodbury-Stewart
Founder and CEO

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

Re: If a, b, and c are integers and a*b^2/c is a positive even   [#permalink] 20 Apr 2017, 15:43
Display posts from previous: Sort by