Last visit was: 11 Dec 2024, 05:48 It is currently 11 Dec 2024, 05:48
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
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 11 Dec 2024
Posts: 97,803
Own Kudos:
Given Kudos: 88,240
Products:
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 97,803
Kudos: 685,031
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
GeorgeKo111
Joined: 21 Jun 2019
Last visit: 15 Nov 2019
Posts: 83
Own Kudos:
Given Kudos: 39
Location: Canada
Concentration: Finance, Accounting
GMAT 1: 670 Q48 V34
GPA: 3.78
GMAT 1: 670 Q48 V34
Posts: 83
Kudos: 73
Kudos
Add Kudos
Bookmarks
Bookmark this Post
avatar
aggarwalanubhav1990
Joined: 31 May 2015
Last visit: 07 Nov 2022
Posts: 5
Own Kudos:
Given Kudos: 117
Posts: 5
Kudos: 2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
avatar
shraddhaFebBorn
Joined: 23 May 2019
Last visit: 05 Nov 2019
Posts: 1
Given Kudos: 7
Posts: 1
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
GeorgeKo111
Before we solve this problem we should note the following properties:

(Odd Number) * (Odd Number) = (Odd Number)
(Even Number) * (Even Number) = (Even Number)
(Odd Number) * (Even Number) = (Even Number)
(Even Number) / (Even Number) = (Even Number)

as per the given: a is an even integer and b is an odd integer:

a^3= (Even Number) * (Even Number) * (Even Number)= (Even Number)

and b^2= (Odd Number) * (Odd Number) = (Odd Number)

(a^3)(b^2)= (Odd Number) * (Even Number) = (Even Number) and 8 is an even number so (a^3)(b^2)/8= Always even(here the question stem did not specify if integer or not so we can assume it can be both)

the correct answer is A.
Can somebody explain why E is the answer?
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 11 Dec 2024
Posts: 97,803
Own Kudos:
Given Kudos: 88,240
Products:
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 97,803
Kudos: 685,031
Kudos
Add Kudos
Bookmarks
Bookmark this Post
shraddhaFebBorn
GeorgeKo111
Before we solve this problem we should note the following properties:

(Odd Number) * (Odd Number) = (Odd Number)
(Even Number) * (Even Number) = (Even Number)
(Odd Number) * (Even Number) = (Even Number)
(Even Number) / (Even Number) = (Even Number)

as per the given: a is an even integer and b is an odd integer:

a^3= (Even Number) * (Even Number) * (Even Number)= (Even Number)

and b^2= (Odd Number) * (Odd Number) = (Odd Number)

(a^3)(b^2)= (Odd Number) * (Even Number) = (Even Number) and 8 is an even number so (a^3)(b^2)/8= Always even(here the question stem did not specify if integer or not so we can assume it can be both)

the correct answer is A.
Can somebody explain why E is the answer?

If a is an even integer and b is an odd integer, then \(\frac{a^3b^2}{8}\)?

A. Always even
B. Always odd
C. Always a fraction
D. Could be a fraction
E. Always an integer

a is an integer, so a = 2k, for some integer k.

\(\frac{a^3b^2}{8}=\frac{(2k)^3b^2}{8}=\frac{8k^3b^2}{8}=k^3b^2=integer\).

Answer: E

A is not always true. Consider a = 2. In this case, \(\frac{a^3b^2}{8}=b^2=odd\)
B is not always true. Consider a = 4. In this case, \(\frac{a^3b^2}{8}=8b^2=even\)
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 11 Dec 2024
Posts: 97,803
Own Kudos:
Given Kudos: 88,240
Products:
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 97,803
Kudos: 685,031
Kudos
Add Kudos
Bookmarks
Bookmark this Post
GeorgeKo111
Before we solve this problem we should note the following properties:

(Odd Number) * (Odd Number) = (Odd Number)
(Even Number) * (Even Number) = (Even Number)
(Odd Number) * (Even Number) = (Even Number)
(Even Number) / (Even Number) = (Even Number)

as per the given: a is an even integer and b is an odd integer:

a^3= (Even Number) * (Even Number) * (Even Number)= (Even Number)

and b^2= (Odd Number) * (Odd Number) = (Odd Number)

(a^3)(b^2)= (Odd Number) * (Even Number) = (Even Number) and 8 is an even number so (a^3)(b^2)/8= Always even(here the question stem did not specify if integer or not so we can assume it can be both)

the correct answer is A.

Only integers can be even or odd.
Moderator:
Math Expert
97803 posts