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 →

If x must be divisible by both 4 and 10, then...

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 2547
Joined: Sun Oct 15, 2017 1:50 pmFollowed by: 6 members
by BTGmoderatorLU » Wed Nov 01, 2017 9:55 am
If x must be divisible by both 4 and 10, then x must also be divisible by which of the following numbers?

A. 8
B. 20
C. 40
D. 50
E. 80

The OA is B.

I don't understand this PS question. Please, can any expert assist me with it? Thanks.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Wed Nov 01, 2017 11:02 am
LUANDATO wrote:If x must be divisible by both 4 and 10, then x must also be divisible by which of the following numbers?

A. 8
B. 20
C. 40
D. 50
E. 80
Let x = the least common multiple of 4 and 10 = 20.
Since x=20 is not divisible by 8, 40, 50, or 80, eliminate A, C, D and E.

The correct answer is B.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 555
Joined: Wed Oct 04, 2017 4:18 pmFollowed by: 12 members
Thanked: 180 times

by EconomistGMATTutor » Fri Nov 03, 2017 3:15 pm
If x must be divisible by both 4 and 10, then x must also be divisible by which of the following numbers?

A. 8
B. 20
C. 40
D. 50
E. 80

The OA is B.

I don't understand this PS question. Please, can any expert assist me with it? Thanks.
Hi LUANDATO,
Let's take a look at your question.

The number that is divisible by both 4 and 10 must the least common multiple of both.
Let's first find LCM of 4 and 10.

Multiples of 4 = 4, 8, 12, 16, 20, ...
Multiples of 10 = 10, 20, 30, 40, ...
LCM = 20

Now 20 is divisible by both 4 and 10.
We need to check that which of the given options is divisible by 20.

OPTION A:
8 is not divisible by 20. So Option A is not correct.

OPTION B:
20 is divisible by 20.
Therefore, Option B is correct.

Hope it helps.
I am available if you'd like any follow up.
GMAT Prep From The Economist
We offer 70+ point score improvement money back guarantee.
Our average student improves 98 points.

Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8139
Joined: Sat Apr 25, 2015 10:56 amFollowed by: 29 members
Location: Los Angeles, CA
Thanked: 43 times

by Scott@TargetTestPrep » Thu Oct 31, 2019 5:24 pm
BTGmoderatorLU wrote:If x must be divisible by both 4 and 10, then x must also be divisible by which of the following numbers?

A. 8
B. 20
C. 40
D. 50
E. 80

The OA is B.

I don't understand this PS question. Please, can any expert assist me with it? Thanks.
If a number is divisible by a and b, then it's also divisible by the LCM of a and b. Therefore, since the LCM of 4 and 10 is 20, then x must be divisible by 20.

Answer: B

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
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1