4.7/4.8 Homework - Permutations vs. Combinations

Front

What is a combination?

Back

A combination refers to ways of choosing items from a large set of objects, where the order does not matter.

Front

What is a permutation?

Back

A permutation refers to ways of arranging items from a set, where the order does matter.

Front

How many ways can the letters in the word 'PARALLEL' be arranged?

Back

3,360

Front

In a class of 12 students, how many ways can three students be ranked in the top 3 positions?

Back

1,320

Front

Electing 4 candidates to a municipal planning board from a field of 7 candidates involves which concept?

Back

Combination

Front

Trying out PIN codes for an ATM card involves which concept?

Back

Permutation

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 have 5 books and want to arrange 3 of them, how many arrangements can you make?

Back

60 (P(5, 3) = 5! / (5 - 3)! = 60)

Front

If you have 10 different shirts and want to choose 4 to take on vacation, how many combinations can you make?

Back

210 (C(10, 4) = 10! / (4!(10 - 4)!) = 210)