Question

There are 20 books on the summer reading list. In how many different ways can you choose one per week for six weeks?

120
21,400
10,350,200
27,907,200

Answer 1

if you know how to do permutations then its 20P6
otherwise, think of it this way..
week 1, you have 20 choices
week 2, you have 19 choices since you already read 1 book
week 3 you have 18 choices ....and so on
--> 20*19*18*17*16*15