NTA Abhyas JEE Main2020MathematicsPermutation and CombinationPractice
The exponent of 7 in 100 C 50 is
Options
- A0
- B1
- C2
- D3
Correct answer
A. 0
Step-by-step solution
We know that, 100 C 50 = 100 ! 50 ! 50 ! The exponent of 7 in 50 ! is 50 7 + 50 7 2 = 7 + 1 = 8 And the exponent of 7 in 100 ! is 100 7 + 100 7 2 = 14 + 2 = 1 6 Thus, the exponent of 7 in 100 C 50 is 16 - 2 × 8 = 0