Combinations

Front

What is a combination?

Back

A selection of items where the order does not matter.

Front

What is a permutation?

Back

An arrangement of items where the order does matter.

Front

When would you use a combination instead of a permutation?

Back

Use a combination when the order of selection is not important.

Front

When would you use a permutation instead of a combination?

Back

Use a permutation when the order of selection is important.

Front

How many ways can you choose 3 players from a team of 17?

Back

680 ways (using combinations).

Front

If you have 5 different books and want to arrange them on a shelf, how many arrangements can you make?

Back

120 arrangements (5! = 5 x 4 x 3 x 2 x 1).

Front

What is the formula for combinations?

Back

C(n, r) = n! / (r!(n - r)!) where n is the total items and r is the items chosen.

Front

What is the formula for permutations?

Back

P(n, r) = n! / (n - r)! where n is the total items and r is the items arranged.

Front

If you have 10 different shirts and want to choose 3 to take on vacation, how many combinations can you make?

Back

120 combinations (C(10, 3)).

Front

If you need to select a president, vice president, and secretary from a group of 5 people, how many ways can you do this?

Back

60 ways (using permutations).