5 schizophrenic women ages 50 59 and 10 eligible controls li

5 schizophrenic women ages 50- 59 and 10 eligible controls live in the same community. How many ways are there of selecting 5 controls?

Solution

There are 10 controls, and we choose 5.

As order does not matter here, we use combinations.

Thus, there are

10C5 = 10!/(5!(10-5)!) = 252 WAYS [ANSWER]