Question

if 21y5 is a multiple of 3 find y​

Answer 1

Answer:

value of y is either 1 or 4 or 7

Step-by-step explanation:

2+1+(4)+5 = 12 , which is also divisible by 3. 2+1+(7)+5 = 15 , which is also divisible by 3. Hence the value of y is either 1 or 4 or 7.