Question

What is C,?
06
O 35
O 210
O 5.040

Answer 1

35

Explanation:

nCr = n! ÷ r!(n - r)!

7C3 = 7! ÷ 3!(7 - 3)!

n! = 7!

7! = 7 x 5 x 4 x 3 x 2 x 1

7! = 5,040

r! = 3!

3! = 3 x 2 x 1

3! = 6

(n - r)! = (7 - 3)!

(7 - 3)! = 4!

4! = 4 x 3 x 2 x 1

4! = 24

7C3 = 5,040 ÷ 6 x 24

7C3 = 5,040 ÷ 144

7C3 = 35