How many three-letter sequences can be made from the letters in the word FORESAW?
We have 7 letters and we're going to grab 3 at a time to make a word. The order that we pick the 3 letters is important - WAS is different than SAW. And so we use the permutation calculation, the general formula is:
We can evaluate in a couple of different ways - one is by using a factorial table:
and the other is by breaking down the multiplication:
Either way, we arrive at 210