A man can row 5 km/h in still water. If the speed of the current is 2.5 km/h, it takes 4 hours more in upstream than in the downstream for the same distance. The distance is:
Answer & explanation
Correct answer: option 2
We know that,
Distance = Speed × Time
Given,
Speed in still water = 5km/h
Speed of upstream = 5km/h - Current speed = 5 - 2.5 = 2.5km/h
Time in upstream = 4 h + Time in Downstream
According to the question,
Distance for Upstream = Distance for downstream
= 2.5 (4 + T) = 7.5T
= 10 + 2.5T = 7.5T
= 5T = 10
= T = 2 h
Now substituting the value of T in Downstream then
= D = 7.5 × 2 = 15km