Question

Show an equation and a solution for the problem. It takes John 20 hours to paint a building. It takes Sam 15 hours to paint the same building. How long will it take for them to paint the building if they work together, with Sam starting one hour later than John? Round to the nearest tenth.

Answer 1

I would say credit each person an amount of work out of 300 (the house), a common number they share. So say that John performs 15 points of work an hour and Sam performs twenty points of work. That means the house is at 285 points remaining. This means that 285/35 (combined) + one hour for John working alone for the first hour is the answer. Your equation should probably look something like this.. give me a moment to dream this up, here...