Question

Compute the following:
7!/3!
a. 1680
b. 840
c. 21
D. 4

Answer 1

7!/3!

7! = 7 X 6 X 5 X 4 X 3 ...

3! = 3 X 2 x 1

since the 3 X 2 X 1 part are repeated in both the numerator and denominator, we can divide them out

7!/3! = 7 X 6 X 5 X 4 = 42 X 20 = b. 840