Aptitude Shortcuts and Mind Tricks for Boats and Streams Problems Type-II – Download in PDF

Dear Readers,Here we have given the Aptitude Shortcuts and Mind Tricks for Boats and Streams Problems Type-II. Candidates those who are preparing for the upcoming examination can also download this in PDF.

A man can row (28/3) km/hr in still water and finds that it takes him thrice as much time to row upstream than as to row downstream the same distance in the stream. What is the speed of the current?

Speed of man in still water, a = (28/3) km/hr

Time taken to travel upstream is thrice as much as the time taken to travel downstream

Let the speed upstream = u km/hr

Then the speed downstream = 3u km/hr

Now the Speed of man in still water = (1/2) × (speed downstream + speed upstream)

Therefore, Speed in still water = (1/2) × (3u + u) = (1/2) × (4u)

                                                 = 2u km/hr

Now speed of man in still water is given as (28/3) km/hr in the question

Therefore, 2u = (28/3)

                   u = (14/3)

So, Speed upstream = u = (14/3) km/hr

Speed downstream = 3u = 3 × (14/3) km/hr = 14 km/hr

Now, Speed of Current = (1/2) × (speed downstream – speed upstream)

                                     = (1/2) × (14 – [14/3])

                                     = (1/2) × ([42 – 14]/3)

                                     = (1/2) × (28/3)

Therefore, the speed of current = (14/3) km/hr

T₁ = time taken to go upstream

T₂ = time taken to go downstream

As per the question, T₁ = 3T₂

Where, speed of man in still water = (28/3) km/hr

Speed of current = (28/3) × ([3T₂-T₂] / [3T₂+T₂])

                           = (28/3) × (2/4)

                           = (28/3) × (1/2)

Therefore, Speed of current = (14/3) km/hr