Discussion
Home ‣ Aptitude ‣ Boats and Streams Comments
- Question
The current of a stream at 1 kmph. A motor boat goes 35 km upstream and back to the starting point in 12 hours. The speed of the motor boat in still water is ?
Options- A. 8 kmph
- B. 6 kmph
- C. 7.5 kmph
- D. 5.5 kmph
- Correct Answer
- 6 kmph
ExplanationSpeed of the stream = 1
Motor boat speed in still water be = x kmph
Down Stream = x + 1 kmph
Up Stream = x - 1 kmph
[35/(x + 1)] + [35/(x - 1)] = 12
x = 6 kmph - 1. A motor boat takes 12 hours to go downstream and it takes 24 hours to return the same distance. what is the time taken by boat in still water?
Options- A. 15 h
- B. 16 h
- C. 8 h
- D. 20 h Discuss
- 2. A boat takes 19 hours for travelling downstream from point A to point B and coming back to a point C which is at midway between A and B. If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph, what is the distance between A and B ?
Options- A. 180 km
- B. 160 km
- C. 140 km
- D. 120 km Discuss
- 3. 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.
Options- A. 12 km/hr, 3 km/hr
- B. 9 km/hr, 3 km/hr
- C. 8 km/hr, 2 km/hr
- D. 9 km/hr, 6 km/hr Discuss
- 4. A man can row 9 km/h in still water. It takes him twice as long as to row down. Find the rate of stream of the river?
Options- A. 3 1⁄3 Kmph
- B. 3 1⁄9Kmph
- C. 4 2⁄3 Kmph
- D. 4 1⁄3 Kmph Discuss
- 5. A boat sails 15 km of a river towards upstream in 5 hours. How long will it take to cover the same distance downstream, if the speed of current is one-fourth the speed of the boat in still water:
Options- A. 1.8h
- B. 3h
- C. 4h
- D. 5h Discuss
- 6. A boy can swim in still water at 4.5 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is ?
Options- A. 1.8 kmph
- B. 2 kmph
- C. 2.2 kmph
- D. 1.5 kmph Discuss
- 7. A man goes down stream with a boat to some destination and returns upstream to his original place in 5 hours. If the speed of the boat in still water and the strean are 10km/hr and 14km/hr respectively, the distance of the destination from the string place is
Options- A. 16 km
- B. 18 km
- C. 21 km
- D. 25 km Discuss
- 8. A man rows his boat 60 km downstream and 30 km upstream taking 3 hrs each time. Find the speed of the stream ?
Options- A. 5 kmph
- B. 10 kmph
- C. 15 kmph
- D. 45 kmph Discuss
- 9. A boatman can row 3 km against the stream in 20 minutes and return in 18 minutes. Find the rate of current ?
Options- A. 1/3 kmph
- B. 2/3 kmph
- C. 1/4 kmph
- D. 1/2 kmph Discuss
- 10. A man can row 6 kmph in still water. When the river is running at 1.2 kmph, it takes him 1 hour to row to a place and back. What is the total distance traveled by the man ?
Options- A. 4.58 kms
- B. 6.35 kms
- C. 5.76 kms
- D. 5.24 kms Discuss
Boats and Streams problems
Search Results
Correct Answer: 16 h
Explanation:
If t1 and t2 are the upstream and down stream times. Then time taken in still water is given by
Correct Answer: 180 km
Explanation:
Speed in downstream = (14 + 4) km/hr = 18 km/hr;
Speed in upstream = (14 ? 4) km/hr = 10 km/hr.
Let the distance between A and B be x km. Then,
x/18 + (x/2)/10 = 19 ? x/18 + x/20 = 19 ? x = 180 km.
Correct Answer: 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,
=> 56p - 56q -28p - 28q = 0
=> 28p = 84q
=> p = 3q.
Now, given that if
Hence, the speed of the boat = p kmph = 9 kmph and the speed of the river flow = q kmph = 3 kmph.
Correct Answer: 4 2⁄3 Kmph
Explanation:
Let man’s rate upstream be x km/hr. Then his rate downstream is 3 x km/hr Given: Speed in still water = 9 (1/3) = 28/3 km/hr i.e, ½ (a+b) = 28/3 km/hr ½ (x+3x) = 28/3 2x = 28/3 x = 28/ 2 x 3 = 14/3 km/hr rate upstream b = 14/3 km/hr and rate downstream a = 14/3 x 3 = 14 km/hr speed of the current = ½ (a-b) = ½ (14 – 14/3) = ½ (42-14/3) = 28/6 = 4 (2/3) km/hr
Correct Answer: 3h
Explanation:
Upstream speed = B-S
Downstream speed = B+s
B-S = 15/5 = 3 km/h
Again B= 4S
Therefore B-S = 3= 3S
=> S = 1 and B= 4 km/h
Therefore B+S = 5km/h
Therefore, Time during downstream = 15/5 = 3h
Correct Answer: 1.5 kmph
Explanation:
Speed of Boy is B = 4.5 kmph
Let the speed of the stream is S = x kmph
Then speed in Down Stream = 4.5 + x
speed in Up Stream = 4.5 - x
As the distance is same,
=> 4.5 + x = (4.5 - x)2
=> 4.5 + x = 9 -2x
3x = 4.5
x = 1.5 kmph
Correct Answer: 21 km
Explanation:
Let the distance covered be D km.
10D = 42 x 5 = 210
=> D = 21 km
Correct Answer: 5 kmph
Explanation:
Speed of the boat downstream s=a/t= 60/3 = 20 kmph
Speed of the boat upstream s= d/t = 30/3= 10 kmph
Therefore, The speed of the stream = =5 kmph
Correct Answer: 1/2 kmph
Explanation:
Speed in upstream = Distance / Time = 3 x 60/20 = 9 km/hr.
Speed in downstream = 3 x 60/18 = 10 km/hr
Rate of current = (10-9)/2 = 1/2 km/hr.
Correct Answer: 5.76 kms
Explanation:
Speed in still water = 6 kmph
Stream speed = 1.2 kmph
Down stream = 7.2 kmph
Up Stream = 4.8 kmph
x/7.2 + x/4.8 = 1
x = 2.88
Total Distance = 2.88 x 2 = 5.76 kms
Comments
There are no comments.More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.