Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?	Choose one.
A) 120 gallons
B) 200 gallons
C) 170 gallons
D) 180 gallons
E) 250 gallons
Work done by the waste pipe in 1 minute = 1/15 - (1/20 + 1/24) = - 1/40   Volume of 1/40 part = 3 gallons\   Volume of whole = 3 * 40= 
<gadget id="calculator">3 * 40</gadget>
<output>120</output>
120 gallons.   120 gallonsNSWER 120 gallons
<result>A</result>
Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?