Question

Which of the following is an example of a combination?
A. Selecting the best cake and runner-up best cake from a cake
decorating competition
B. Selecting 5 CDs to take with you on a trip from a collection of 30
CDs
C. The number of orders in which 6 people can arrive at a party if no
one arrives at the same time
D. The number of orders in which triplets can be born

Answer 1

Answer: Choice B

Explanation:

For choice A, order matters. This is because of the positions of first place and second place are different from one another. Since order matters, we have a permutation for choice A and can rule it out.

Choices C and D are ruled out for the same reason.

Choice B is a combination. It doesn't matter what the order of the CDs are. All that matters is the group overall rather than the individual CDs.