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
Vote for Target Test Prep, Newsweek Readers’ Choice Awards 2026
NEWSWEEK READERS’ CHOICE 2026

BIG NEWS! Target Test Prep has been nominated, and they’d love your vote!

TTP has worked incredibly hard to build the best test prep experience possible, and winning Newsweek’s 2026 Readers’ Choice Award for Best Test Prep would mean a lot to them. If TTP has helped you, they’d be incredibly grateful for your vote. You can vote once each day through September 9.

Vote for TTP
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & 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.

GMAT Prep - LCM

Expert replies
Source: — Data Sufficiency |

by ildude02 » Wed Jun 18, 2008 8:14 pm
I couldn't think of a concrete and simpler way, except for solving by using numbers. If we can find the value of x, we should be able to solve the problem.

statement 1 gives LCM of 30 ,so when cnosiderign the factors of 30, (1,2,3,5,6,10,15, 30). All the multiples of 5 can give LCM of 30. And when we substitue these multiples of 5 in the question, we always get LCM 90.

Applying the same logic for statement 2, we can find the LCM. So D the answer.

I would appreciate if there is a definite properties of LCM we could use instead of using numbers since it did take some to figure out the answer.
Join the discussion

by Ian Stewart » Wed Jun 18, 2008 8:49 pm
There's one thing you can learn about LCMs that makes this question quite easy:

to find the LCM of x, y, and z, you can first find the LCM of x and y, then find the LCM of this number with z.

That might sound confusing at first- the point is this: what is the LCM of 6, 8 and 10? You don't need to do it all at once. You can find the LCM of 6 and 8 first, which is 24, then find the LCM of 24 and 10 (which is 120). Or we could have found the LCM of 6 and 10 first (which is 30), then the LCM of 30 and 8 (again, we get 120). And so on.

Okay, on to the question:

The question asks, what is the LCM of x, 6 and 9.

From 1), the LCM of x and 6 is 30. By the discussion above, the question is just 'what is the LCM of 30 and 9?' Sufficient.

From 2), the LCM of x and 9 is 45. So the question is asking, 'what is the LCM of 45 and 6?'. Sufficient.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com
Join the discussion

by alexdallas » Sat Jul 18, 2009 9:16 am
tks Ian
great explanation
Join the discussion