A man can row a boat at 10km/h in still water. If the speed of the stream is 7km/h, what is the time taken to row a distance of 85km down the stream?
- A5 hours
- B4 hours
- C6 hours
- D3 hours
Solution & Step-by-step Explanation
Given:
Speed of the boat in still water (u) = 10km/h
Speed of the stream (v) = 7km/h
Downstream speed (D) is given by the formula:
D=u+v
D=10+7=17km/h
The distance to be covered downstream is 85km.
The formula for time taken is:
Time=
Speed
Distance
Time=
17
85
=5hours
Speed of the boat in still water (u) = 10km/h
Speed of the stream (v) = 7km/h
Downstream speed (D) is given by the formula:
D=u+v
D=10+7=17km/h
The distance to be covered downstream is 85km.
The formula for time taken is:
Time=
Speed
Distance
Time=
17
85
=5hours