Pipes A, B and C can fill a tank in 15, 30 and 40 hours, respectively. Pipes A, B and C are opened at 6 a.m., 8 a.m. and 10 a.m., respectively, on the same day. When will the tank be full?
Two person P and Q are 844 m apart. They both start cycling simultaneously in the same direction with speeds of 12 m/s and 8 m/s, respectively, In how much time will P overtake Q?