Question

Which of the following numbers is divisible by 3 and 9?

A. 74,028
B. 40,653
C. 62,997
D. 95,376

Answer 1

Well if it's divisible by 9 then it's automatically divisible by 3, because 3 divides 9.
To test this there's a dirty trick: you add the digit of the number all together, and if the sum divisible by 9, then the whole number is divisible by 9.

Answer 2

Example : for 74,028 we sum up all the digits 7+4+0+2+8 = 21
21 is not divisible by 9 so 74,028 is not divisible by 9.
Can you try for the second number ?