The ratio of the speed of the boat in still water to the speed of the stream is 8:3 and the boat can travel 22 km downstream in 24 minutes. Then, how much time will the boat take to cover 50 km upstream?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 2 hrs.
Let the speed of the boat in still water = 8x km/hr
Speed of the stream = 3x km/hr
Downstream speed = 8x + 3x = 11x km/hr
(11x) × (24/60) = 22
⇒ 2x/5 = 2
⇒ x = 5
⇒ 8x = 8 × 5 = 40
⇒ 3x = 3 × 5 = 15
Upstream speed = 40 - 15 = 25 km/hr
Time taken to cover 50 km upstream = 50/25 = 2 hours