1.When boatman A travels from point X to Y then the river has no speed of stream. He covers half the distance at a speed of 21 km/hr and the rest with a speed of ‘x’ km/hr which took him an overall time of 2 hours and 24 minutes. When boatman B travels from point X to Y with the speed of boat as 21 km/hr then the river has a speed of stream of 3 km/hr and he has to travel the entire distance at upstream. If boatman B took 2 hours and 20 minutes to cover the distance then find the value of ‘x’.
- 12 km/hr
- 14 km/hr
- 15 km/hr
- 16 km/hr
- None of these
2.A boatman rows ‘y’ km downstream and ‘y/2′ km upstream. A fish whose speed is 6 km/hr in still water moves against the stream and covers 3 km in 1 hour. If the speed of boatman in still water is 15 km/hr and the total time taken by the boatman to cover the whole distance is 3.5 hours, then find the value of ‘y’.
- 42 km
- 36 km
- 35 km
- 40 km
- None of these
3.The speed of boat A and B in still water is ‘3x’ km/hr and ‘7y’ km/hr respectively whereas the speed of stream A and B is ‘y’ km/hr and ‘2x’ km/hr respectively. Boat A can cover 105 km in 3 hours while travelling in stream A downstream. Boat B can cover 90 km in 6 hours while travelling in stream B upstream. What would be boat A’s speed while travelling in stream A upstream?
- 25 km/hr
- 5 km/hr
- 15 km/hr
- 45 km/hr
- None of these
4.Time taken by boat to travel a distance of 180 km upstream is 30 minutes more than the time taken by boat to travel the same distance downstream, and the time taken to travel a distance of 160 km downstream is equal to the time taken to travel 144 km upstream. Find the speed of the boat in still water.
- 42 km/hour
- 40 km/hour
- 38 km/hour
- 36 km/hour
- 34 km/hour
5.A boat can go 80 Km downstream and 72 Km upstream in 14 hours. It can go 144 Km downstream and 88 Km upstream in 20 hours. If the speed of the boat in still water is increased by 25% and speed of the stream is increased by 1 Km/h, Find the sum of downstream distance travelled by the boat in 4 hours and upstream distance travelled by the boat in 6 hours.
- 140 km
- 240 km
- 180 km
- 160 km
- 120 km
6.A boat travelling upstream has to reach its destination by 03:00 p.m. The boat started at 12 noon and was travelling with a speed of 10 km/hr in still water to cover one-fourth of the distance, after which the river started flowing 20% faster against the boat. What should be the percentage increase in the still water speed of the boat so as to reach just in time? Given that the speed of flow is 5 km/hr and total distance to be covered is 20 km.
- 10%
- 20%
- 35%
- 15%
- 25%
7.Find the average speed of the boat in still water and the speed of the stream.
- The ratio of time taken by boat to cover a certain distance in upstream to that of in downstream is 3: 2 from the same distance as in upstream.
- Total time taken by boat to go 36 km far and comes back to the original point in the stream is 5 hours.
- Boat takes 25 hours to cover 45 km distance in downstream.
- Only Il alone is sufficient.
- Only Ill alone is sufficient.
- Only I and Il together are sufficient.
- Either Ill alone or I and Il together are sufficient.
- All l, Il and Ill together are sufficient.
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