Q. A boat goes 40 km upstream in 8 hours and 36 km downstream in 6 hours. The speed of the boat in still water is:
Answer:
5.5 km/hr
Notes: Speed upstream $ = \frac{40}{8} = 5km/hr$
Speed downstream $ = \frac{36}{6} = 6 km/hr$
∴ Speed of boat in still water $ = \frac{1}{2}(5+6) = 5.5 km/hr$
Hence option [B] is correct answer.