Problem of the Week Sept. 8

Solve this problem at your own level.  There are multiple ways to solve it.

Upon entering a tall building, you are confronted with a problem that has existed since the late

nineteenth century—should you take the stairs, or the elevator? If you decide to take the stairs,

it will take you 20 seconds to walk up each flight of stairs. If you decide to take the elevator,

you will have to wait for 3 minutes for the elevator to arrive, after which it will take 3 seconds

to move up each floor. Compute the minimum number of floors for which taking the elevator

takes less time than taking the stairs.