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

Redeem

What is the greatest prime factor of \(3^6 - 1?\)

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: What is the greatest prime factor of \(3^6 - 1?\)

by Scott@TargetTestPrep » Tue Nov 17, 2020 8:40 am
Gmat_mission wrote: ↑
Tue Nov 10, 2020 7:53 am
 What is the greatest prime factor of \(3^6 - 1?\)

A. 2
B. 3
C. 7
D. 13
E. 17

Answer: D

Solution:

Since 3^6 - 1 = (3^3 + 1)(3^3 - 1) = 28 x 26 = 2^2 x 7 x 2 x 13, we see that its largest prime factor is 13.

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