2021 · Q95
There is a remainder of 4 when a number is divided by 7. What will be the remainder if the square of the same number is divided by 7?
Elementary MathematicsNumber System
- A5
- B3
- C4
- D2
Explanation
Write the number as 7q + 4. Squaring: 49q² + 56q + 16 = 7(7q² + 8q + 2) + 2, so the remainder is 2. Hence option D.