Numbers - General Aptitude

Q1:

If the number 517*324 is completely divisible by 3, then the smallest whole number in the place of * will be:

A

B 1

C 2

D None of these

ANS:C - 2

Sum of digits = (5 + 1 + 7 + x + 3 + 2 + 4) = (22 + x), which must be divisible by 3.   x = 2.