remainder when xy is divided by 10

[abhi332]

If x = 3 ^ 21 and y = 6 ^ 55, what is the remainder when xy is divided by 10?

(A) 2

(B) 3

(C) 4

(D) 6

(E) 8

[spoiler]OA:E[/spoiler]

[firdaus117]

Dividing by 10 and getting the remainder is same as determining the unit's digit of xy.Now you can do it yourself,can't you?.

[abhi332]

Thanks firdaus117,

3 ^ 21 * 6 ^ 55
= ...3 * ...6
= ...8

so when divided by 10 will give 8 as the Ans