- A10.5 hours
- B9 hours
- C10 hours
- D12 hours
Step-by-Step Solution
Downstream = 84 ÷ 6 = 14 km/h. Speeds are inverse to times, so km/h. Time = 63/14 + 63/10.5 = 4.5 + 6 = 10.5 h.
Answer: A) 10.5 hours
Over the same stretch, a boat's upstream and downstream times are in the ratio 4 : 3. Downstream it covers 84 km in 6 hours. How long will a trip of 63 km downstream and 63 km back take?
Competition practiceBoats & Streams
Master this topic in 30 minutes a day.
Don't just memorise the answer — build a daily practice habit.
Practice 5 Similar Questions Free →All Boats & Streams practice questions
More Boats & Streams practice
A launch does the same out-and-back run once on a still lake and once on a flowing river…On any fixed stretch, a boat's downstream trip takes 20% less time than its upstream…For an out-and-back trip, a student takes the simple mean of a boat's downstream speed…Anjali can swim at 2 km/h in still water, but the river flows at 3 km/h. She swims…A boat completes a 30 km round trip (15 km out, 15 km back) on a calm lake in 4 hours.…