Last visit was: 23 Apr 2026, 06:10 It is currently 23 Apr 2026, 06:10
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,778
Own Kudos:
810,775
 [7]
Given Kudos: 105,853
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,778
Kudos: 810,775
 [7]
Kudos
Add Kudos
7
Bookmarks
Bookmark this Post
User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 23 Apr 2026
Posts: 6,976
Own Kudos:
16,906
 [4]
Given Kudos: 128
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Products:
Expert
Expert reply
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
Posts: 6,976
Kudos: 16,906
 [4]
1
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
User avatar
Alingan
Joined: 12 Jun 2023
Last visit: 17 Feb 2025
Posts: 4
Own Kudos:
1
 [1]
Given Kudos: 66
Posts: 4
Kudos: 1
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Nikkz99
Joined: 23 Jun 2021
Last visit: 30 Mar 2026
Posts: 85
Own Kudos:
Given Kudos: 1,274
Location: India
GPA: 3.54
Posts: 85
Kudos: 48
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Alingan
GMATinsight
Bunuel
If the last digit of a seven digit number is 4 and the remaining six digits add up to 23, then the original number must be:

A. divisible by 7
B. divisible by 18
C. divisible by 23
D. divisible by 27
E. a prime number

Last digit is 4 i.r. number is divisible by 2
Sum of the seven digits = 23+4 = 27 i.e. Number is divisible by 9 (Sum of digits must be divisible by 9)

hence result must be divisible by 2*9 = 18

Answer: Option B
Why shouldn't the same number be divisible by 27?
3*9=27
Question states "MUST BE" rather than "COULD BE", so...
Prime factors of 18 -> 2 * 3^2

so, given number must be divisible by 2 (since last digit is given as 4, the number is divisible by 2)
and sum of digits of the number must be divisible by 9 , since 23+4 -> 27 therefore, number is divisble by 9

Hope it helps.
Moderators:
Math Expert
109778 posts
Tuck School Moderator
853 posts