Question

Lori Bray drives a parcel delivery truck. Her usual route consists of 10 stops. How many ways can Lori travel to these stops and return to her warehouse?
A. 90

B. 3,628,800

C. 362,880

D. 10

Answer 1

How many options does she have for where to make her first stop?
Once she has made her first stop, how many options does she have for her second?
Her third stop?
Fourth stop?
Fifth?
...

Answer 2

Great explanation, bro.

Answer 3

haha thanks though!(;

Answer 4

Jamie, the thing Luis posted, 10!
means "ten factorial" and it's a short way of writing
10*9*8*7*6*5*4*3*2*1

Which happens to be what I was trying to lead you up to. She has 10 choices for stop 1. 9 Choices for stop 2, since she's already been to one house. 8 choices for stop 3, since she's already been to two houses. And so one. 7 choices, 6, 5, 4, 3, 2, and finally, for her last stop she only has 1 choice.

And in general, any time you have n things, and you're choosing an order to put them in, there will be n! different orders.