A tank with a volume of 30 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 9 cubic inches/min and 8 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)	Choose the correct option:
A) 1440	B) 2340	C) 3240	D) 4320	E) 5420
The tank is emptied at this rate: 9 + 8 - 5= 
<gadget id="calculator">9 + 8 - 5</gadget>
<output>12</output>
12 cubic inches/min   The tank has a volume of  30*12*12*12= 
<gadget id="calculator"> 30*12*12*12</gadget>
<output>51_840</output>
51840 cubic inches.   The time it takes to empty the tank is 51840/12= 
<gadget id="calculator">51840/12</gadget>
<output>4_320</output>
4320 minutes.   The answer is 4320.
<result>D</result>
A tank with a volume of 30 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 9 cubic inches/min and 8 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)