A cistern has a leak which would empty the cistern in 20 minutes. A tap is turned on which admits 3 liters a minute into the cistern, and it is emptied in 24 minutes. How many liters does the cistern hold? Choose the correct choice:
A) 360  B) 487  C) 481  D) 729  E) 268
1/x - 1/20 = -1/24   x = 120   120 * 3= 
<gadget id="calculator">120 * 3</gadget>
<output>360</output>
360   360nswer:360
<result>A</result>
A cistern has a leak which would empty the cistern in 20 minutes. A tap is turned on which admits 3 liters a minute into the cistern, and it is emptied in 24 minutes. How many liters does the cistern hold?