The downstream speed of a boat is 20 km/hr and the speed of stream is 4 km/hr.…
2021
The downstream speed of a boat is 20 km/hr and the speed of stream is 4 km/hr. What will be the total time taken by the boat to cover 160 km downstream and 96 km upstream?
Answer: A. 16 hours — Downstream: Downstream speed = 20 km/hr. Distance = 160 km. Time (downstream) = Distance / Speed = 160 / 20 = 8 hours. Upstream: Boat speed in still water =…
- A.
16 hours
- B.
12 hours
- C.
14 hours
- D.
10 hours
Attempted by 74 students.
Show answer & explanation
Correct answer: A
Downstream:
Downstream speed = 20 km/hr.
Distance = 160 km.
Time (downstream) = Distance / Speed = 160 / 20 = 8 hours.
Upstream:
Boat speed in still water = Downstream speed - Stream speed = 20 - 4 = 16 km/hr.
Upstream speed = Boat speed in still water - Stream speed = 16 - 4 = 12 km/hr.
Distance = 96 km.
Time (upstream) = Distance / Speed = 96 / 12 = 8 hours.
Total Time:
Total Time = Time (downstream) + Time (upstream) = 8 + 8 = 16 hours.
Final Answer: Option 1 (16 hours)