In what time would a cistern be filled by three pipes whose diameters are 1 cm,`1 1/3` cm and 2 an running together, when the largest alone will fill it in 61 minutes, the amount of water flowing in by each pipe, being proportional to the square of its diameter? `25\ m inu t e s` b. `30\ m inu t e s` c. `36\ m inu t e s` d. `40\ m inu t e s`

A thief running at 8 km/hr is chased by a policeman whose speed is 10 km/hr. If the thief is 100 metres ahead of the policeman, then the time required for the policeman to catch the thief will be 2 m inu t e s b. 3 m inu t e s c. 6 m inu t e s d. 10 m inu t e s

A runs twice as fast as B and B runs thrice as fast as C. The distance covered by C in 72 minutes, will be covered by A in 12 m inu t e s b. 16 m inu t e s c. 18 m inu t e s d. 24 m inu t e s

A bath can be filled by the cold water pipe in 10 minutes and by the hot water pipe in 15 minutes. A person leaves the bathroom after turning on both the pipes' Ile returns just when the bath should have been full. Finding however, the waste pipe was open, he closes it. In 4 minutes more, the bath is full. In what time will the waste water pipe empty it? 6\ m inu t e s b. \ 8\ m inu t e s c. 9\ m inu t e s d. none of these

The diameter of three pipes are 1cm, 1 (1)/(3) cm and 2 cm respectively. The quantity of water flowing through a pipe varies directly as the square of its diameter. If the pipe with 2 cm diameter can fill a tank in 61 minutes, in what time will all the three pipes together fill the tank?