Question
A boat can travel 30 km downstream in 2 hours and 18 km upstream in 3 hours. How much time (in hours) will it take to travel 21 km in still water?
Solution
ATQ, Downstream speed = 30/2 = 15 km/h Upstream speed = 18/3 = 6 km/h Let boat speed in still water = b, stream speed = s. b + s = 15 b − s = 6 Add: 2b = 21 → b = 10.5 km/h Time in still water for 21 km: = 21 / 10.5 = 2 hours.
More Boats and streams Questions
- A man rows 40 km upstream and 60 km downstream in 8 hours. If the ratio of his upstream speed to downstream speed is 2:3, then find the time required to tr...
- A boat takes 7 hours to cover 294 km upstream and 9 hours to cover 486 km downstream. Find the time taken by the boat to cover 720 km upstream and 616 km d...
- A boat's speed in still water is 200% greater than the speed of the stream. The boat takes 13 hours to travel 180 km downstream and 66 km upstream. How muc...
- A boat takes 7 hours to cover 259 km upstream and 9 hours to cover 477 km downstream. Find the time taken by the boat to cover 645 km upstream and 660 km d...
- A boat running downstream covers a distance of 55 km in 5 hrs and covering the same distance upstream in 11 hrs. What is the speed of a boat in still water...
- A Motarboat running upstream takes 6 hours and 45 minutes to cover a distance, while it takes 3 hours to cover the same distance running downstream. Determ...
- Speed of a boat in still water is three times the speed of the boat in upstream. If the boat takes 25 minutes to cover 25 km in downstream, then find the s...
- A boy can swim in water with a speed of 12 km/hr in still water. If the speed of the stream is 5 km/hr, what will be the time taken by the boy to cover 68 ...
- Speed of boat in downstream is 45% more than speed of boat in still water. If speed of stream is 9 km/h, then find the time taken by the boat to cover 81 k...
- A boat moves downstream at 45 km/h, which is (25/10) m/s faster than its upstream speed. If it covers (D + 24) km downstream and (D - 36) km upstream in a ...
