Three taps A, B and C can fill a tank in 24, 30 and 40 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full in :	Choose the correct option
A) 8 hours  B) 10 hours  C) 14 hours  D) 16 hours  E) 18 hours
(A+B)'s 1 hour's work = (1/24 + 1/30) = 9/120 = 3/40.   (A+C)'s 1 hour's work = (1/24 + 1/40) = 8/120 = 2/30.   Part filled in 2 hours = (3/40 + 2/30) = 17/120.   Part filled in 12 hours = (6 * 17/120) = 17/20.   Remaining part = (1 - 17/20) = 3/20.   now, it is the time of A and B and 3/20 part is filled by A and B in 1 hour, then, 3/40 part will filled in 2 hours.   .'. total time taken to fill the tank = (12 + 2)= 
<gadget id="calculator">(12 + 2)</gadget>
<output>14</output>
14 hours Answer : 14 hours
<result>C</result>
Three taps A, B and C can fill a tank in 24, 30 and 40 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full in :