Question

A textbook search committee is considering 13 books for possible adoption. The committee has decided to select 8 of the 13 for further consideration. In how many ways can it do​ so?

Answer 1

This is asking for the number of combinations in which you can pick 8 books out of a group of 13.
The general formula for finding combinations is:

`\left(\begin{array}{ccc}n\\k\end{array}\right) = (n!)/(k! (n-k)!)`
For this example where n = 13, k = 8

`(13!)/(8! *5!) = (13*12*11*10*9)/(5*4*3*2*1) = 13*11*9 = 1287`