Question

A bookshelf holds `24` mysteries, `12` non-fiction books, and `4` biographies. What is the probability of selecting a mystery book and then without replacing it, selecting a non-fiction book?

Answer 1

`12/65` or roughly 18%

Explanation:

The bookshelf holds `24+12+4=40` books altogether.

First let’s find the probability of selecting a mystery book:

There are 24 mysteries out of 40 total books, so the probability is `24/40=60%`

Now we need to select a non-fiction book out of the remaining 39 books. That probability would be `12/39=4/13`

Using the counting principle we must multiply these numbers together on the numerator and denominator (basically just multiply the fractions), so:

`3/5*4/13=12/65`

Thus the probability is roughly 18%.