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

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Integers

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
User avatar
Master | Next Rank: 500 Posts
Posts: 422
Joined: Mon Aug 09, 2010 11:47 amFollowed by: 1 member
Thanked: 22 times
GMAT Score:680

by beatthegmatinsept » Mon Sep 20, 2010 3:11 pm
IMO C.
From a) we know 2, 2 and 5 are factors of n
From b) we know 3 is a factor of n

In order for n to be a multiple of 15, n should have factors: 3 and 5

Together a and b give you 2, 3 and 5 as factors of n. Hence Sufficient.
Being defeated is often only a temporary condition. Giving up is what makes it permanent.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 659
Joined: Mon Dec 14, 2009 8:12 amFollowed by: 3 members
Thanked: 32 times

by Gurpinder » Mon Sep 20, 2010 5:20 pm
danjuma wrote:3. Is the integer n a multiple of 15?

a. n is a multiple of 20
b. n+6 is a multiple of 3
yes/no question

(a) prime factors of n are 5,2,2 and more....... hence insufficient by itself. if we had a 3, then this one would be sufficient.
(2) since 6 is also a multiple of 3, n+6 is also a multiple of 3. which means that n is a multiple of 3.

now n can be 3 which is a multiple of 3 but not 15. or n can be 15 which is a multiple of 3 and 15.

hence insufficient.

together:

we know that n+6 is a multiple of 3. hence the prime factors of n has a 3 in it.

so taking 5,2,2 and 3 from (b), we can make a 15. hence n is a multiple of 15.

hence (c)
"Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress."
- Alfred A. Montapert, Philosopher.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1