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

Redeem

Which of the following is NOT a prime factor of

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8086
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

Re: Which of the following is NOT a prime factor of

by Scott@TargetTestPrep » Sat Nov 28, 2020 1:42 pm
BTGmoderatorDC wrote: ↑
Sun Nov 15, 2020 4:57 pm
 Which of the following is NOT a prime factor of (5^6−2^6)?

A. 3
B. 7
C. 13
D. 17
E. 19


OA D

Solution:

Factoring (5^6−2^6) as a difference of two squares, we have:

(5^3 + 2^3)(5^3 - 2^3) = (125 + 8)(125 - 8) = 133 x 117 = 7 x 19 x 9 x 13 = 3^2 x 7 x 13 x 19

We see that 17 is not a factor of 5^6 − 2^6.

Answer: D

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
Post new topic Post Reply
• Page 1 of 1