Newton's law of cooling & mixture

A cylindrical tank 24 inches in radius and 2 meters tall initially contains 100 gal of canejuice. A level sensor is installed in the tank which signals an alarm once 70% of the total Volume of the tank has been reached. At t = 0, a cane juice containing 43% sugar is poured into the tank at a rate (if 15 gpm. while the wellstirred mixture leaves at a rate of 5 gram. Assuming that due to operator negligence. this process continued at constant rates, after how man)f minutes will the alarm sound? Use 1 gal = 3.785 Li