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 ? Answers
A) 0 B) 1 C) 3 D) 4 E) 2
Let the number be x and on dividing x by 5, we get k as quotient and 3 as remainder.   x=5k+3   x^2=(5k+3)^2=(25k^2+30k+9)   =5(5k^2+6k+1)+4   on dividing x^2 by 5,we get 4 as remainder.   Answer is 4
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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 ?