Question

if21y5 is multiple of 9 where y is a digit .what is the value of y​

Answer 1

Answer:

1

Step-by-step explanation:

A number is divisible by 9 when the sum of its digit is invisible by 9

So, If 21y5 is a multiple of 9(or divisible by nine), sum of its digit would also be divisible by 9

2+1+y+5=8+y. (substituting y by 1) 2+1+1+5= 9

9 is divisible by 9. So, by substituting y by 1 we can make this number a multiple of 9.

We can see that 1 is the only possible value which can be given to y.