Question

One Saturday, you decided to invite some friends over to watch movies that you found on a list of the top 100 movies of all time. You have narrowed it down to 7 movies, but your friends only have time to stay for 5. How many different group of movies can you watch in the time available?

Answer 1

Number of available movies to watch = 7

Number of movies that we need to select = 5

This can be done in $7C_{5}$ ways.

$7C_{5} = \frac{7!}{5! 2!}$

$= \frac{6(7)}{2}$

= 21 ways

Hence, 5 movies can be selected from the available 7 movies in 21 ways.