Combinations & Permutations

Front

What is a permutation?

Back

A permutation is an arrangement of objects in a specific order. The order of arrangement matters.

Front

What is a combination?

Back

A combination is a selection of objects where the order does not matter.

Front

How do you calculate permutations of n objects taken r at a time?

Back

The formula is nPr = n! / (n - r)!

Front

How do you calculate combinations of n objects taken r at a time?

Back

The formula is nCr = n! / (r! * (n - r)!)

Front

What is the value of 20P2?

Back

20P2 = 20! / (20 - 2)! = 20! / 18! = 20 * 19 = 380.

Front

If you have 14 shirts, 4 pants, and 2 pairs of shoes, how many outfits can you create?

Back

You can create 14 * 4 * 2 = 112 different outfits.

Front

How many different cars can be ordered with 3 engines, 8 colors, and 2 transmissions?

Back

You can order 3 * 8 * 2 = 48 different cars.

Front

How many ways can a club select a president, vice president, and secretary from 5 people?

Back

The number of ways is 5P3 = 5! / (5 - 3)! = 5 * 4 * 3 = 60.

Front

What is the value of 15P8?

Back

15P8 = 15! / (15 - 8)! = 15! / 7! = 15 * 14 * 13 * 12 * 11 * 10 * 9 * 8 = 259459200.

Front

What is the factorial of a number?

Back

The factorial of a number n (denoted as n!) is the product of all positive integers up to n.