Problem: a tank with a volume of 45 cubic feet has one inlet pipe and 2 outlet pipes . the inlet pipe fills water into the tank at the rate of 5 cubic inches / min and the 2 outlet pipes empty it out at the rates of 14 cubic inches / min and 6 cubic inches / min respectively . if all 3 pipes are opened when the tank is full , how many minutes does it take to empty the tank ? ( 1 foot = 12 inches )
Rationale: "the tank is emptied at this rate : 14 + 6 - 5 = 15 cubic inches / min the tank has a volume of 45 * 12 * 12 * 12 = 77760 cubic inches . the time it takes to empty the tank is 77760 / 15 = 5184 minutes . the answer is a ."
annotated_formula: divide(multiply(45, power(14, 5)), subtract(add(12, 6), 5))