On dividing a number by 5, we get 3 as remainder. What will be the remainder when the square of this number is divided by 5 ?  Choices
A) 0  B) 1  C) 3  D) 4  E) 2

Rationale: let the number be x and on dividing x by 5 , we get k as quotient and 3 as remainder . x = 5 k + 3 x ^ 2 = ( 5 k + 3 ) ^ 2 = ( 25 k ^ 2 + 30 k + 9 ) = 5 ( 5 k ^ 2 + 6 k + 1 ) + 4 on dividing x ^ 2 by 5 , we get 4 as remainder . answer is d
Answer: D