logo

CuriousTab

CuriousTab

Discussion


Home Aptitude Boats and Streams Comments

  • Question
  • If sum of upstream and downstream speed of a boat is 82 kmph, and the boat travels 105 km. upstream in 3 hr, Find the time taken by boat to cover 126 km downstream.


  • Options
  • A. 2.8 hrs
  • B. 2.7 hrs
  • C. 2.6 hrs
  • D. 2.5 hrs

  • Correct Answer
  • 2.7 hrs 

    Explanation

    Let Speed of boat in still water = b

    Let Speed of still water = w

    Then we know that,

    Speed of Upstream = U = boat - water

    Speed of Downstream = D = boat + water

    Given, U + D = 82

    b - w + b + w = 82

    2b = 82

    => b = 41 kmph

    From the given data,

    41 - w = 105/3 = 35

    w = 6 kmph

    Now,

    b + w = 126/t

    => 41 + 6 = 126/t

    => t = 126/47  = 2.68 hrs.


  • Boats and Streams problems


    Search Results


    • 1. In one hour, a boat goes 12 km/hr along the stream and 6 km/hr against the stream. The speed of the boat in still water (in km/hr) is:

    • Options
    • A. 9
    • B. 8
    • C. 7
    • D. 7.5
    • Discuss
    • 2. A motorboat can go 10 miles downstream on a river in 20 min. It takes 30 min for this boat to go back at the same 10 miles. Find the speed of the current ?

    • Options
    • A. 8 m/h
    • B. 5 m/h
    • C. 7 m/h
    • D. 6 m/h
    • Discuss
    • 3. A man can row 8 kmh in still water. If the river is running at 2 kmh, it takes 4 hrs more upstream than to go downstream for the same distance. Then the distance is given by

    • Options
    • A. 54 kms
    • B. 32 kms
    • C. 45 kms
    • D. 60 kms
    • Discuss
    • 4. A boat whose speed in still water is 9 kmph, goes 12 km downstream and comes back in 3 hrs. Find the speed of the stream?

    • Options
    • A. 1 kmph
    • B. 3 kmph
    • C. 5 kmph
    • D. 4 kmph
    • Discuss
    • 5. 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?

    • Options
    • A. 7:4
    • B. 11:4
    • C. 4:7
    • D. 8:3
    • Discuss
    • 6. A boat travels 72 km downstream in 8 hours and 84 km upstream in 12 hours. Find the speed of the boat in still water and the speed of the water current ?

    • Options
    • A. 9 and 3 kmph
    • B. 6 and 7 kmph
    • C. 8 and 1 kmph
    • D. 7 and 2 kmph
    • Discuss
    • 7. A boatman can row 96 km downstream in 8 hr. If the speed of the current is 4 km/hr, then find in what time he will be able to cover 8 km upstream ?

    • Options
    • A. 1.5 hrs
    • B. 1 hrs
    • C. 2.5 hrs
    • D. 2 hrs
    • Discuss
    • 8. Rajesh rows in still water with a speed of 4.5 kmph to go to a certain place and comes back. Find his average speed for the whole journey, if the river is flowing with a speed of 1.5 kmph?

    • Options
    • A. 2 kmph
    • B. 4 kmph
    • C. 6 kmph
    • D. 8 kmph
    • Discuss
    • 9. Find the speed of stream if a boat covers 36 km in downstream in 6 hours which is 3 hours less in covering the same distance in upstream?

    • Options
    • A. 1.5 kmph
    • B. 1 kmph
    • C. 0.75 kmph
    • D. 0.5 kmph
    • Discuss
    • 10. A man can row against the current three fourth of a kilometer in 15 min and returns same distance in 10 min, then ratio of his speed to that of current?

    • Options
    • A. 5:1
    • B. 3:1
    • C. 4:1
    • D. 2:1
    • Discuss


    Comments

    There are no comments.

Enter a new Comment