logo

CuriousTab

CuriousTab

Discussion

Home ‣ Aptitude ‣ Boats and Streams Comments
  • Question

  • 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

  • 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,

    2   x   28 p   +   q   =   28 p   -   q

     

    => 56p - 56q -28p - 28q = 0

    => 28p = 84q

    => p = 3q.

    Now, given that if

    28 3 q   +   2 q   +   28 3 q   -   2 q   =   672 60 = >   28 5 q   +   28 q   =   672 60 = >   q   =   3   kmph = >   x     = 3 q   =   9   kmph

     

    Hence, the speed of the boat = p kmph = 9 kmph and the speed of the river flow = q kmph = 3 kmph.

    • Boats and Streams problems

    Search Results

    • 1. 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
    • 2. 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
    • 3. Two consecutive discounts x% and y% is equivalent to the discount

    • Options
    • A. (x-y+xy100)%
    • B. (x+y+xy100)%
    • C. (x-y-xy100)%
    • D. (x+y-xy100)%
      • Discuss
    • 4. The certain worth of a certain sum due sometime hence is Rs. 1600 and the true discount is Rs. 160. The banker's gain is:

    • Options
    • A. 15
    • B. 16
    • C. 14
    • D. 13
      • Discuss
    • 5. The banker's discount of a certain sum of money is Rs. 72 and the true discount on the same sum for the same time is Rs. 60. The sum due is:

    • Options
    • A. 290
    • B. 480
    • C. 360
    • D. 420
      • Discuss
    • 6. 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
    • 7. 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
    • 8. 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
      • Discuss
    • 9. 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
    • 10. 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

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.