1. 2 pumps of different sizes, working together, can empty a fuel tank in 5 hours. The larger pump can emty this tank in 4 hours less than the smaller one. If the larger one is out of order, how long will it take the smaller one to do the job alone?

2. How much water must be evaporated from 32 ounces of a 4% salt solution to make a 6% salt solution?