I have four books, each with n pages, and I can read them all in four hours.

I have four more books, each with each 120 fewer pages than my original four books. I can read them all in three hours.

I have five more books, each with 120 more pages than my original four books. How long would it take me to read all five books?

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?

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?

If Jameson can build a 20 foot wall in 6 hours, and Jaqueline can build a 50 foot wall in 12 hours, and the two of them work together to build a 180 foot wall (with each of them starting at opposite ends of the wall), how much wall will each build before the wall is complete?