permutation and combination

Front

What is a permutation?

Back

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

Front

What is a combination?

Back

A combination is a selection of objects where the order does not matter. It focuses on the group rather than the arrangement.

Front

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

Back

The formula is n! / (n - r)!, where n is the total number of objects and r is the number of objects to arrange.

Front

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

Back

The formula is n! / (r! * (n - r)!), where n is the total number of objects and r is the number of objects to choose.

Front

What is the difference between permutations and combinations?

Back

Permutations consider the order of selection, while combinations do not.

Front

How many ways can you choose 2 items from a set of 15?

Back

15C2 = 105 ways.

Front

If you have 4 different fruits and want to choose 2, how many combinations can you make?

Back

4C2 = 6 combinations.

Front

In how many ways can you arrange 3 books on a shelf?

Back

3! = 6 ways.

Front

What is the total number of different pizzas you can create with 8 meats, 4 cheeses, 3 crusts, and 2 sauces?

Back

8 x 4 x 3 x 2 = 192 different pizzas.

Front

How many different ways can you choose 2 questions from 5 on a test?

Back

5C2 = 10 ways.