Boats and Streams - General Questions (2)
| 9. | The speed of a boat in still water in 15 km/hr and the rate of current is 3 km/hr. The distance travelled downstream in 12 minutes is: |
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Answer: Option D Explanation: Speed downstream = (15 + 3) kmph = 18 kmph.
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km = 3.6 km.| 10. | 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? |
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Answer: Option B Explanation:
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Speed in still water =| 11. | In one hour, a boat goes 11 km/hr along the stream and 5 km/hr against the stream. The speed of the boat in still water (in km/hr) is: |
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Answer: Option C Explanation: Speed in still water =1/2(11 + 5) kmph = 8 kmph. |
| 12. | A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is: |
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Answer: Option B Explanation: Let the speed of the stream be x km/hr. Then, Speed downstream = (15 + x) km/hr, Speed upstream = (15 - x) km/hr.
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| 13. | A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively? |
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Answer: Option C Explanation: Let the man's rate upstream be x kmph and that downstream be y kmph. Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.
= 8 : 3. |
| 14. | A man's speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man's speed against the current is: |
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Answer: Option C Explanation: Man's rate in still water = (15 - 2.5) km/hr = 12.5 km/hr. Man's rate against the current = (12.5 - 2.5) km/hr = 10 km/hr. |
| 15. | A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, find the time taken by the boat to go 68 km downstream. |
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Answer: Option C Explanation: Speed downstream = (13 + 4) km/hr = 17 km/hr.
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