Boats and Streams Problems Practice Question and Answer
8 Q: A motorboat whose speed is 20 km/h in still water takes 30 minutes more to go 24 km upstream than to cover the same distance downstream. If the speed of the boat in still water is increased by 2 km/h, then bow much time will it take to go 39 km downstream and 30 km upstream?
637 0646ca32ecdae930acb92492f
646ca32ecdae930acb92492f- 13 h 40 mfalse
- 22 h 40 mfalse
- 33 h 10 mtrue
- 42 h 50 mfalse
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Answer : 3. "3 h 10 m"
Q: 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. 52782 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 man can row with the stream at 9 km/hr. and against the stream at 3 km/hr. His speed in still water is -
3482 0608fc0278ab61162923103bb
608fc0278ab61162923103bb- 112 km/hrfalse
- 25 km/hrfalse
- 310 km/hrfalse
- 46 km/hrtrue
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Answer : 4. "6 km/hr"
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.
6131 0608fb6257748471dd98ccd2a
608fb6257748471dd98ccd2a- 117false
- 215false
- 313true
- 49false
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Answer : 3. "13"
Q: Speed of a boat in still water is 12 kmph and that of the current is 3 kmph. A man row a boat upstream up to 135 km and return downstream to the starting point. Find the total time taken for the entire journey in hours.
1062 0606aed55556643278a727fbc
606aed55556643278a727fbc- 136false
- 248false
- 330false
- 424true
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Answer : 4. "24"
Q: Speed of boat in upstream is 11km/hr and downstream is 23 km/hr find the speed of boat in still water?
1179 0601a4d68c12de45b38e1ef91
601a4d68c12de45b38e1ef91- 115 km/hrfalse
- 217 km/hrtrue
- 39 km/hrfalse
- 48 km/hrfalse
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Answer : 2. "17 km/hr"
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?
1252 05f2a7064a5ce9779bd292e5a
5f2a7064a5ce9779bd292e5a- 132false
- 230true
- 331false
- 433false
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Answer : 2. "30"
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 :
1597 05f23ec4e3494c5438aa834dc
5f23ec4e3494c5438aa834dc- 14 hrtrue
- 27 hrfalse
- 32 hrfalse
- 43 hrfalse
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