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

Redeem

Is the sum of two integers divisible by 10 ?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Mon Apr 29, 2019 8:16 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

AbeNeedsAnswers wrote:Is the sum of two integers divisible by 10 ?

(1) One of the integers is even.
(2) One of the integers is a multiple of 5.
Target question: Is the sum of two integers divisible by 10 ?

Statement 1: One of the integers is even.
We only have information about ONE number.
Statement 1 is NOT SUFFICIENT

Statement 2: One of the integers is a multiple of 5.
We only have information about ONE number.
Statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
There are many possible pairs of values that satisfy BOTH statements. Here are two:
Case a: The numbers are 10 (even) and 10 (divisible by 5). So, the sum = 20, which means the answer to the target question is YES, the sum of the integers IS divisible by 10.
Case b: The numbers are 2 (even) and 15 (divisible by 5). So, the sum = 17, which means the answer to the target question is NO, the sum of the integers is NOT divisible by 10.
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer: E

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Mon May 20, 2019 11:25 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Hi All,

We're asked if the sum of two integers is divisible by 10. This is a YES/NO question can be solved by TESTing VALUES.

(1) One of the integers is even.

Fact 1 tells us about just one of the numbers; we know nothing about the other number. For organizational purposes, I'll refer to the 2 numbers as X and Y.
IF....
X = 10 and Y = 0, then the answer to the question is YES.
X = 10 and Y = 5, then the answer to the question is NO.
Fact 1 is INSUFFICIENT

(2) One of the integers is a multiple of 5.

Fact 2 tells us about just one of the numbers; we know nothing about the other number. The TESTs that we used for Fact 1 also fit the information in Fact 2 (it's worth noting that 0 IS a multiple of 5).
IF....
X = 10 and Y = 0, then the answer to the question is YES.
X = 10 and Y = 5, then the answer to the question is NO.
Fact 2 is INSUFFICIENT

Combined, we know...
One of the integers is even.
One of the integers is a multiple of 5.

Since we already have two examples that fit both Facts, there's no more work to be done - the answer could be either 'YES' or 'NO.'
Combined, INSUFFICIENT

Final Answer: E

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Post new topic Post Reply
• Page 1 of 1