**Pipes A, B and C can fill a tank in 30 h, 40 h and 60 h respectively. Pipes A, B and C are opened at 7 a.m., 8 a.m., and 10 a.m. respectively on the same day. When will the tank be full?** A) 10.00 p.m. B) 10.20 p.m. C) 9.20 p.m. D) 9.40 p.m. Click Link for Answer