Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 2 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is? Choose the correct choice from the following answers:
A) 60 gallons	B) 100 gallons	C) 120 gallons	D) 80 gallons	E) 130 gallons
Work done by the waste pipe in 1 minute = 1/15 - (1/20 + 1/24) = - 1/40   Volume of 1/40 part = 2 gallons\   Volume of whole = 2 * 40= 
<gadget id="calculator">2 * 40</gadget>
<output>80</output>
80 gallons.   ANSWER:80 gallons
<result>D</result>
Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 2 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?