Question

If 21y5 is a multiple of 9, where y is a digit , what is the value of 9

Answer 1

Step-by-step explanation:

we know that if we add all number together and if the sum of this number is divisible by 9 so 21y5 is also divisible by 9

so,

2+1+5 if we add we get,8

so we have to put 1 instead of y

so the answer is y=1