Tips and Tricks on Boats and Streams related Aptitude Problems

  1. Downstream/Upstream:In water, the direction along the stream is called downstream. And, the direction against the stream is called upstream.
  2. If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then:

    Speed downstream = (u + v) km/hr.

    Speed upstream = (u – v) km/hr.

  3. If the speed downstream is a km/hr and the speed upstream is b km/hr, then:
    Speed in still water = 1 (a + b) km/hr.
    Rate of stream = 1 (a – b) km/hr.
    1.A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, find the time taken by the boat to go 68 km downstream.
    A. 2 hours
    B. 3 hours
    C. 4 hours
    D. 5 hours

    Answer: Option C


    Speed downstream = (13 + 4) km/hr = 17 km/hr.

    Time taken to travel 68 km downstream = 68 hrs = 4 hrs.


    2.A man’s speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man’s speed against the current is:
    A. 8.5 km/hr
    B. 9 km/hr
    C. 10 km/hr
    D. 12.5 km/hr

    Answer: Option C


    Man’s rate in still water = (15 – 2.5) km/hr = 12.5 km/hr.

    Man’s rate against the current = (12.5 – 2.5) km/hr = 10 km/hr.

    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?

    A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:

    In one hour, a boat goes 11 km/hr along the stream and 5 km/hr against the stream. The speed of the boat in still water (in km/hr) is:

    A boat running downstream covers a distance of 16 km in 2 hours while for covering the same distance upstream, it takes 4 hours. What is the speed of the boat in still water?

    The speed of a boat in still water in 15 km/hr and the rate of current is 3 km/hr. The distance travelled downstream in 12 minutes is:

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