Samwise can mow 5 lawns in 9 hours, and Frodo can mow 1 lawn in 4 hours. Samwise, Frodo, and Bilbo, working together, can mow 20 lawns in 18 hours. How many minutes does it take Bilbo to mow 3 lawns?

A clock adjusts its timing each night by contacting a satellite at 2:00 AM to find out the official standard time. Since it has a mechanical action with physical minute, second and hour hands, if the clock finds out it is out of sync, it will move at 12 times normal speed in order to "catch up" with the actual time. (If it is ahead of the correct time, it will still move forward, until it wraps around to the correct time.)

In the fall, when Daylight Savings Time happens, at 2:00 the satellite tells the clock that it is actually 1:00. Thus, the clock has to move forward at high speed until it wraps around to the correct time.

How long will it take the clock to be displaying the correct time again?

Marco walks a certain distance at a certain speed (measured in miles per hour), and then returns over the same distance at a speed one mph less than his original walking speed. He took a total of 35 hours. If, instead of slowing down for his return journey, he had sped up by one mph, his journey would have taken 27 hours. How far did he walk?

John drove at 20 mph for 30 minutes, and then he drove back home at 10 mph. What was his average speed for the entire trip?