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 ? a . 480 liters
1 / x - 1 / 20 = - 1 / 24 x = 120 120 * 4 = 480 answer : a
multiply(divide(multiply(24, 4), subtract(24, 20)), 20)