A cistern has a leak which would empty the cistern in 20 minutes. A tap is turned on which admits 4 liters a minute into the cistern, and it is emptied in 24 minutes. How many liters does the cistern hold?	Answers
A) 480 B) 266 C) 287 D) 1661 E) 211
1/x - 1/20 = -1/24   x = 120   120 * 4= 
<gadget id="calculator">120 * 4</gadget>
<output>480</output>
480   480nswer: 480
<result>A</result>
A cistern has a leak which would empty the cistern in 20 minutes. A tap is turned on which admits 4 liters a minute into the cistern, and it is emptied in 24 minutes. How many liters does the cistern hold?