Question: A number when divide by 6 leaves a remainder 3. When the square of the number is divided by 6, the remainder is:
[A].0
1
2
3
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
Let x = 6q + 3.
Then, x2 = (6q + 3)2
= 36q2 + 36q + 9
= 6(6q2 + 6q + 1) + 3
Thus, when x2 is divided by 6, then remainder = 3.