Boats and Streams Problems Practice Question and Answer
8Q: A man went downstream for 28 km in a motor boat and immediately returned. It took the man twice as long to make the return trip. If the speed of the river flow were twice as high, the trip downstream and back would take 672 minutes. Find the speed of the boat in still water and the speed of the river flow. 52331 05b5cc672e4d2b4197774c0c8
5b5cc672e4d2b4197774c0c8- 112 km/hr, 3 km/hrfalse
- 29 km/hr, 3 km/hrtrue
- 38 km/hr, 2 km/hrfalse
- 49 km/hr, 6 km/hrfalse
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Answer : 2. "9 km/hr, 3 km/hr"
Explanation :
Answer: B) 9 km/hr, 3 km/hr Explanation: Let the speed of the boat = p kmph Let the speed of the river flow = q kmph From the given data, 2 x 28p + q = 28p - q => 56p - 56q -28p - 28q = 0 => 28p = 84q => p = 3q. Now, given that if 283q + 2q + 283q - 2q = 67260=> 285q + 28q = 67260=> q = 3 kmph=> x =3q = 9 kmph Hence, the speed of the boat = p kmph = 9 kmph and the speed of the river flow = q kmph = 3 kmph.
Q: A swimmer can swim 68 km downstream and 45 km upstream in 9 hours and he will take 2 hours more to swim 51 km downstream and 72 km upstream. Find the speed of the swimmer in still water.
5749 0608fb6257748471dd98ccd2a
608fb6257748471dd98ccd2a- 117false
- 215false
- 313true
- 49false
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Answer : 3. "13"
Q: A man rows to a place 35 km in distance and back in 10 hours 30 minutes. He found that he can row 5 km with the stream in the same time as he can row 4 km against the stream. Find the rate of flow of the stream?
4104 05f23edc41436461f6a2f678f
5f23edc41436461f6a2f678f- 11.33 km/hrfalse
- 21.5 km/hrfalse
- 31 km/hrfalse
- 40.75 km/hrtrue
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Answer : 4. "0.75 km/hr"
Q: A man can row with the stream at 9 km/hr. and against the stream at 3 km/hr. His speed in still water is -
2655 0608fc0278ab61162923103bb
608fc0278ab61162923103bb- 112 km/hrfalse
- 25 km/hrfalse
- 310 km/hrfalse
- 46 km/hrtrue
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Answer : 4. "6 km/hr"
Q: If the speed of a boat in still water is 20 km/hr and the speed of the current is 5 km/hr, then the time taken by the boat to travel 100 km with the current is :
1414 05f23ec4e3494c5438aa834dc
5f23ec4e3494c5438aa834dc- 14 hrtrue
- 27 hrfalse
- 32 hrfalse
- 43 hrfalse
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Answer : 1. "4 hr"
Q: 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? 1336 05b5cc6bce4d2b4197774d88b
5b5cc6bce4d2b4197774d88b- 17:4false
- 211:4false
- 34:7false
- 48:3true
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Answer : 4. "8:3"
Explanation :
Answer: D) 8:3 Explanation: Let the speed of the boat upstream be p kmph and that of downstream be q kmph Time for upstream = 8 hrs 48 min = 845hrs Time for downstream = 4 hrs Distance in both the cases is same. => p x 845= q x 4 => 44p/5 = 4q => q = 11p/5 Now, the required ratio of Speed of boat : Speed of water current = q+p2:q-p2 => (11p/5 + p)/2 : (11p/5 - p)/2 => 8 : 3
Q: Ratio between speed of boat in still water to speed of stream is 7 : 2. If 126 km is travelled downstream in 3.5 hours then find the difference between speed of boat in still water to speed of stream(in kmph)?
1274 05df9b6329e7c624c9bfe82fd
5df9b6329e7c624c9bfe82fd- 115false
- 222false
- 324false
- 420true
- 518false
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Answer : 4. "20"
Q: If a boat goes upstream at a speed of 24 km/hr and comes back the same distance at 40 km/hr. What is the average speed (in km/hr) for the total journey?
1070 05f2a7064a5ce9779bd292e5a
5f2a7064a5ce9779bd292e5a- 132false
- 230true
- 331false
- 433false
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