A manufacturer uses a tank to supply water to his machines while they

A manufacturer uses a tank to supply water to his machines while they are working. When the machines are on the tank loses 1.5 gallons of water an hour at the same time 1 gallon of water is pumped into the tank from a well. Write an equation that models the amount of water (w) in the tank for any hour (h) that the machines are on. The tank starts full with 150 gallons of water in it.