Jack can mow a lawn in 6 hours, and Jane can mow it in 4 hours. If they work together, how long will it take them to mow the lawn? Give your answer in minutes.

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?

A car travels from city A to city B in 12 hours. It then travels from city B to city C at the same speed, in 8 hours. If the car was traveling 5 mph faster, it would have traveled from city A to city B in 10 hours.  What is the distance from city B to city C?

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?

Owen can read a 100 page book, which had 500 words per page. It took him 2 hours less time than it takes him to read a 150 page book with 600 words per page. How long would it take him to read a 400 page book which had 400 words per page?

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?

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?