Question

Roxie is picking out some movies to rent, and she is primarily interested in horror films and foreign films. She has narrowed down her selections to 20 horror films and 8 foreign films. How many different combinations of 3 movies can she rent if she wants at least two horror films?

Answer 1

She has 2,660 combinations

Explanation:

Here, we want to calculate the number of different combinations of 3 movies that can be rented

The condition is at least two horror movies

What this means is that she can select 2 or 3 horror movies

if two horror movies, then 1 foreign film

The combination is as follows;

20 C 2 * 8 C 1

= 190 * 8 = 1,520

If she is selecting 3 horror movies, then no foreign film will be selected

Number of ways this can be done is;

20 C 3 = 1,140

So the

number of different combinations would be;

1,140 + 1,520 = 2.660