Question

The remainder when 5⁹⁹isdividedby 13

• A. 7
• B. 8
• C. 9
• D. 10

Answer 1

Answer: (B)

8

Answer 2

Suppose total number of students be n.

Then ⁿC₂ = 66

Ž $\frac{n!}{(n - 2)!2!}$ = 66

Ž n(n – 1) = 132 Ž n² – n –132 = 0

Ž (n – 12) (n + 11) = 0

Ž n = 12, – 11

Ž n = 12