Question

Tick (✓) the correct answer
If the 4-digit number x27y is exactly divisible by 9, then the least value of (x + y) is
(a) 0
(b) 3
(c) 6
(d) 9

Answer 1

(d) 9

If a number is divisible by 9, then the sum of the digits is divisible by 9.

$x+2+7+y=(x+y)+9$
For this to be divisible by 9, the least value of $(x+y)\mathrm{is}0$.
But for x+y = 0, x and y both will be zero.
Since x is the first digit, it can never be 0.
∴ x + y + 9 = 18
or x + y = 9