7.2 Combinations and Permutations Topic Check

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 do you calculate 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

How do you calculate 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

What does ₁₀C₅ represent?

Back

The number of ways to choose 5 items from a set of 10 without regard to the order.

Front

What does ₁₀P₅ represent?

Back

The number of ways to arrange 5 items selected from a set of 10.

Front

If a student takes 4 classes from 6 available classes, how many combinations are there?

Back

15 combinations.

Front

What is the formula for calculating the number of ways to choose r items from n items?

Back

C(n, r) = n! / (r!(n - r)!)

Front

What is the formula for calculating the number of ways to arrange r items from n items?

Back

P(n, r) = n! / (n - r)!.

Front

In a race with 25 participants, how many ways can the top 8 finishers be selected?

Back

1,081,575 ways.