Question

How many combinations of four books can be made from eight different books? 24 70 1,680?

Answer 1

70

Explanation:

Answer 2

70

Explanation:

four books can be made from eight different books

4 books to be chosen from 8 books

The order does not matters so we use Combination.

four books can be made from eight different books, so we find 8C4

`nCr= (n!)/(r!(n-r)!)`

`8C4= (8!)/(4!(8-4)!)`

`8C4= (8!)/(4!(4)!)`

`8C4= (8*7*6*5*4!)/(4!(4)!)=70`