Permutations or combinations? Permutations Answer: 720
Practice makes perfect
We want to find how many ways there are to take six different classes. Note that, in this case, the order is important. Therefore, each possible arrangement is a permutation. To calculate the answer, we will use the formula for permutations of n objects taken r at a time.
_n P_r = n!/(n-r)!
We have six classes and are taking six at a time. This means that both n and r are 6. Let's substitute 6 for n and 6 for r in the above formula.
