Two pipes A and B can fill a cistern in 16 and 24 minute respectively both fill pipes are opened together but 4 minutes before the cistern take to fill pipe B is closed. In how much time the cistern will get filled.
(a) 13 min
(b) 57/5min
(c) 11 1/5 min.
(d) 10 min
Sol:
In 4 min B can fill = 2 × 4 = 8 unit
