Fred lives on the 16th floor. The elevator goes up one floor for each 10 seconds.

It stops at the fifth floor for 1 minute for people to get out.

How long does it take for Fred to get to the 16th floor?

Explain how you figure this out.

It takes 3:40. By the time it is at the fifth floor it has already taken 1:50 seconds including the minute wait. At the 6th floor it is at 2 minutes. When it is at the twelfth floor it has been 3 minutes. And when it gets to the 16th floor it has been 3 minutes and 40 seconds (3:40)

16 x 10

160 seconds - 2 min 40 sec

2 min 40 sec + 1 min

3 min 40 sec