Combinations and Permutations

Front

What is a combination?

Back

A selection of items from a larger set where the order does not matter.

Front

What is a permutation?

Back

An arrangement of items from a larger set where the order does matter.

Front

How many different area codes can be created if the first digit can be 2-9, the second digit can be 0 or 1, and the third digit can be 0-9?

Back

160

Front

What is the formula for combinations?

Back

C(n, r) = n! / (r!(n - r)!) where n is the total number of items, and r is the number of items to choose.

Front

What is the formula for permutations?

Back

P(n, r) = n! / (n - r)! where n is the total number of items, and r is the number of items to arrange.

Front

If you are choosing 3 toppings from a list of 15, what method do you use?

Back

Combination.

Front

If you are arranging 7 players in a batting order from a team of 12, what method do you use?

Back

Permutation.

Front

How many outcomes are there for picking a day of the week and a month of the year?

Back

84 (7 days x 12 months).

Front

How many different combinations of 4 classes can be chosen from 6 available classes?

Back

15.

Front

What is the difference between combinations and permutations?

Back

Combinations do not consider order, while permutations do.