How do I solve combination and permutation problems?

How do I solve combination and permutation problems?

To solve these problems, you need to understand the difference between combinations and permutations. Combinations are selections where order doesn't matter, while permutations are arrangements where order does matter.

Can you give me an example of a combination problem?

Sure! If you have 5 fruits and want to choose 2, the number of combinations is calculated using the formula C(n, r) = n! / (r!(n-r)!). So, C(5, 2) = 5! / (2!3!) = 10.

What about a permutation example?

For permutations, if you want to arrange 3 books out of 5, you use the formula P(n, r) = n! / (n-r)!. So, P(5, 3) = 5! / 2! = 60.

How do I know when to use combinations or permutations?

Use combinations when the order of selection doesn't matter, and use permutations when the order is important.