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

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATBootcamp Starts Sep 28
Chris Peckover, Target Test Prep GMAT expert
LIVE ONLINE BOOTCAMP

Live Online Bootcamp Class with Top GMAT Expert Chris Peckover

15 live classes from Sep 28, 2026

Schedule
Mon to Fri · 7:00 to 10:00 PM ET
Included
Live classes + 6 months of TTP OnDemand
  • Boost your GMAT score in less than one month in a live online class
  • 6 months access to TTP OnDemand video courses included
View bootcamp & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

hardest DS in 15 testset

Expert replies
Source: — Data Sufficiency |

Re: hardest DS in 15 testset

by Andrei » Thu Oct 29, 2009 9:00 am
Hi,
If x is a multiple of 6, it can be written as:
x = 2*3*k, k - positive integer.
If y is a multiple of 14, it can be written as:
y = 2*7*m, m - - positive integer.

So, xy = 2*3*2*7*k*m.

105 can be written as: 105 = 3*5*7

So, in order that xy to be an multiple of 105, it has to be divisible by 3, 5 and 7.
As xy is already divisible by 2, 3 and 7, it has to be divisible by 5 too, thus either k or m must be divisible by 5.

a. x a multiple of 9 - NOT SUFFICIENT
b. y is multiple of 25 -> so m is divisible by 5 - SUFFICIENT

My answer is B.
Join the discussion