A number when divided by 5 leaves a remainder 3. What is the remainder when its square is divided by 5?
Show answer & explanation
Correct answer: C
Explanation
Remainder when the number is divided by 5 = 3
Number = 5k + 3
Square of the number = (5k + 3)²
= 25k² + 30k + 9
= 5(5k² + 6k + 1) + 4
Remainder when divided by 5 = 4