1.  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
B. 1
C. 2
D. 3

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.