If X and Y are the two digits of the number 347XY such that the number is completely divisible by 80, then what is the value of X + Y?

Answer: Option A

Given: 347XY where X, Y two digit number is completely divisible by 80.
$$\begin{array}{rl}& \frac{347XY}{80}=\frac{347XY}{8\times 10}\\ & \frac{7+X+Y}{8}\end{array}$$
∴ Y must be zero
So, go through option A
Put X = 2, then number 3472 is divisible by 8.