A man rows a boat upstream and covers a distance of 8 km in 2 hour. When he rows the boat downstream, he covers the same distance in 80 minutes. The speed of the boat in still water is :
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 5 km/hr
Speed of boat in still water = x km/hr
Speed of current = y km/hr
Speed of upstream = $\frac{Distance}{Time}=\frac{8}{2}=4km/hr$
$⇒x-y=4$ ...(1)
$x+y=6$ ....(2)
Add (1) and (2)
$2x=10$
$x=5km/hr$