Question

If 21y5is a multiple of 9, where y is a digit, what is the value of y

Answer 1

Answer:

ACCORDING TO THE DIVISIBILITY RULE OF 9 WHEN WE ADD ALL THE DIGITS AND IF THE SUM IS DIVISIBLE BY 9 THEN THE NUMBER IS DIVISIBLE BY 9.

2+1+y+5=8+y

so y= 1 as when we add 1 to 8 we get 9 which is divisible by 9