Question

21y5 is a multiple of 3 then value of y is=

Answer 1

Hello mate !!

The sum of digits of a multiple of 9 must be equal to 9 
Therefore 2+1+y+5 = 9 
y = 9-2-1-5 
y=1 
The value of y = 1

Hope it helpful

Answer 2

A number is divisible by 3 if the sum of all digits of the number is divisible by 3.

2+1+y+5 must be divisible by 3.
8+y must be divisible by 3.
So, y can be 1,4,7.

Therefore value of y can be 1, 4 or 7.



Hope it helps uh❤