Question

You have the first season of your favorite television show on a set of DVDs. The set

contains 10 episodes. You have time to watch 2 episodes. How many combinations
of 2 episodes can you watch?

Answer 1

Answer: There are 45 combinations.

Explanation:

If the order in which you watch the episodes does not matter, then we can use the combinatory defined as:

If we have N elements, and we want to make groups of K elements, we have

`C(N,K) = (N!)/((N-K)!*K!)`

combinations.

In this case, we have a total of N = 10 episodes, and we want to make groups of K = 2.

Then we have:

`C = (10, 2) = (10!)/(8!*2!) = (10*9)/(2) = 5*9 = 45`

There are 45 combinations.