Question

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?

Answer 1

Rate downstream = 16/2 kmph = 8 kmph.
Rate upstream = 16/4 kmph = 4 kmph.
Speed in still water = 1/2 (8 + 4) kmph = 6 kmph.

hope this will help you...

Answer 2

Answer:              speed                distance(km)           Time(hr)     Speed(km/hr)

Downstream        b+ s                        16                              2                    16/2 = 8

Upstream             b-s                           16                             4                     16/4 = 4

b + s = 8

b - s = 4

Explanation:

b = 8+4/2 = 12/2 = 6km/hr

b = speed of boat

s = speed/velocity of stream