GMAT Avengers Study Group Practice Question 4

[helen.xia@mbawatch]

NO EXPERT REPLY NEEDED!

A is a 15-digit integer. Is A divisible by 9?

1) Each digit of A is divisible by 3
2) The sum of all digits of A is 72

[theCodeToGMAT]

To find: Is A divisible by 9

Statement 1:
Each digit is divisible by "3"..
That means digits can be "3" or "6" or "9"
This doesn't guarantee that Sum will be divisible by "9" ..
INSUFFICIENT


Statement 2:
Sum of Digits is 72 and it is divisible by "9"
SUFFICIENT

Answer [spoiler]{B}[/spoiler]?

[mevicks]

A is a 15-digit integer. Is A divisible by 9?
1) Each digit of A is divisible by 3
2) The sum of all digits of A is 72

Note: A number is divisible by 9 if the sum of its digits is divisible by 9

Q: Is the 15 digit no. divisible by 9

St1:
333333333333333 --> Sum of the digits = 3*15 = YES 45 is divisible by 9
333333333333339 --> Sum of the digits = 3*14 + 9 = NO 51 is not divisible by 9
INSUFFICIENT

St2:
Directly gives the property.
SUFFICIENT

[spoiler]Answer : B[/spoiler]