A boat covers a distance of 51 km downstream in 3 hours and takes $7\frac{2}{7}$ hours to cover the same distance upstream. If the boat's speed in still water is 12 km/hrs, then the speed of the stream is:

A boat covers 32 km upstream and 36 km downstream in 7 hours. Also, it covers 40 km upstream and 48 km downstream in 9 hours. The speed of the boat in still water is:

A boat goes downstream at a speed of 18 km/hr and upstream at a speed of 'm' km/hr. The boat travelled 90 km downstream in a river and then returned back taking altogether 12.5 hours. Then which of the following are true ?

A. $m = 12$

B. $m = 15$

C. Speed of water current is 3 km/hr

D. Speed of water current is 1.5 km/hr

Choose the correct answer from the options given below:

In a 500 metres race, the ratio of speeds of two participants Meena and Kamal is 4:5 respectively. If Meena has a start of 200 metres, find the distance by which Meena wins.

'A' can run 1km in 5 minutes 20 seconds and 'B' can run the same distance in 6 minutes. How many meters start can 'A' give 'B' in a kilometer race so that they finish the race together?

A boat goes 24 km upstream in 4 hours and 32 km downstream in 4 hours. The speed of the boat in still water is:

A motorboat completes a round trip of 150 km between two places A and B in 8 hours. If downstream speed of the motorboat is 25 km/hr, then the upstream speed of the motorboat is