- #1
zak100
- 462
- 11
Homework Statement
Josh works on the second floor of a building. There are 10 doors to the building and 8 staircases from 1st to the 2nd floor. Josh decided that each day he would enter by one door and leave by a different one and go up one stair case and down another. How many days could Josh do this before he had to repeat a path he had previously taken?
Homework Equations
The Attempt at a Solution
For one day: Possibilities for choosing a door are 10 * 9
For one day: Possibilities for choosing a Stair case are 8 * 7
I don't know after how many days he would repeat the path.
Zulfi.