Question

if 21y is a multiple of 9 , where y is a digit, what is the value of y?

Answer 1

if 21y is a multiple of 9.

then the value of y=6.
because a number is said to divisible by if the sum of its digits are divisible by 9.
so if we take y=6
= 2+1+6
=9
:-) 9 is divisible by 9
hence 6 is the value of y

:-)hope it helps u.