Question

A number when divided by 5 leaves a remainder 3 what is the remainder when the squares of the same are is divided by 5

Answer 1

Let the Number is y.

when y is divided by 5 by multiplying with a number,(let x) gives remainder 3.

so y can be written as..

y =5x +3
if we square...

y^2 =(5x+3)^2

y^2=25x^2+2(5x)(3)+9

y^2=25x^2+30x+9

y^2=5(5x^2+6x)+5+4

y^2=5(5x^2+6x+1)+4

so the remainder will 4