3 pipes can fill a reservoirin 10,15 and 20 hrs. resp. The first was opened at 5 a.m. , the second at 6 a.m., third at 7 a.m. When will the reservoir the filled?

The ratio between the rate of walking of x and y is 2:3. If the time taken by B to cover a certain distance is 24min, to cover the same distance A will take:

A boatman goes 2 km against the current of the stream in 1 hour and goes 1km along the current in 10 minutes. How long will it take to go 5 km in stationary water?

Three friends A, B and C run around a circular track of length 120 metres at speeds of 5 m/s, 7 m/sec and 15 m/sec, starting simultaneously from the same point and in the same direction. How often will the three of them meet?

A car travels a distance of 360km at a uniform speed. If speed of the car is 20km/hr more then time is 3 hrs. less.The original speed of car was:

In a watch, the minute hand crosses the hour hand for the third time exactly after every 3 hrs 18 min 15 seconds of watch time. What is the time gained or lost by this watch in one day?

A man in a train notices that he can count 21 telephone posts in one minute. If they are known to be 50 metres apart, then at what speed in the train travelling?

A Boat running downstream covers a distance of 16 km in 2 hours while for covering the same Distance upstream it takes   4 hours. What is the speed of the boat in still water?