Question

If 21x5 is a multiple of 9, where x is a digit, what is the value of x?​

Answer 1

Answer:

any number which is divisible by 9 is a multiple of 9 so to find the multiple of 9 the sum of given number should be divisible by 9

2 + 1 + 5 is equal to 8 and if we will add one in these numbers then we will get 9 and 9 is divisible by 9 so the X value is 1

Answer 2

the value of x is 1

because

when we add 2+1+1+5 = 9

and it is divisible by 3

so, it is divisiblity rule of 9