Work Backwards

Sometimes, the best method for problem solving can be working backwards.  To do this, the question would need to provide you a final answer.  You can take this solution along with any other information you know to find an original value that you're being asked for.

Example:  Jeff decided to walk from his house to Oliver's house. It took him 45 minutes to walk from his house to Jason's house. Then it took another 35 minutes for them to walk from Jason's to Oliver's. They arrived at Oliver's at 2:45 P.M. At what time did Jeff leave his house?