A large tank of sterile water holds 200 gallons . It is leaking at an unknown rate. At 8:30 am the tank had 137 gallons and at 11:00 am the tank had 115 gallons. Assuming the tank was full when the leak began , write a function to estimate how much water is in the tank. now find the time at which the tank began leaking and the time at which the tank will be empty.