Question
A launch moves 50 km upstream and 180 km downstream in a combined time of 11 hours. The still-water speed of the launch is 10 km/h faster than the stream. Find the stream speed.
Solution
Let the speed of the stream = x And the speed of the boat in still water = x + 10 50/(x + 10 − x) + 180/(x + 10 + x) = 11 50/10 + 180/(2x + 10) = 11 5 + 180/(2x + 10) = 11 180/(2x + 10) = 6 2x + 10 = 180/6 2x + 10 = 30 2x = 20 x = 10 The speed of the stream = 10 km/hr
More Boats and streams Questions
- The speed of the boat in still water is 9 km/hr and the speed of the stream is 6 km/hr. A boat goes 90 km downstream with its usual speed but at the time o...
- A motorboat covers 48 km downstream and 30 km upstream in 6 hours. Under the same conditions, it covers 64 km downstream and 20 km upstream also in 6 hours...
- A boat travels 200 km downstream in 10 hours. The difference between its downstream speed and upstream speed is 5 km/h. What is the ratio of the boat's spe...
- A boat takes half the time to move a certain distance downstream than upstream. the ratio of the boat's speed in still water and that of the current is.
- A boy can swim a certain distance downstream in 2 hours and return in 5 hours. If the rate of stream is 3 kmph then what is the speed of boy in still water...
- A boat covers 42 km downstream in 3 hours and 30 km upstream in 5 hours. What is the speed of the boat in still water?
- The combined speeds of boats 'P' and 'Q' in still water amount to 52 km/hr. The current's speed affecting boat 'P' is 25% greater than that affecting boat ...
- A takes 3 hours more while swimming upstream than downstream. His speed in still water is 12 km/hr. The speed of stream is 4 km/hr. What is the distance?
- A boat travels 30 km downstream in 2 hours and the same distance upstream in 5 hours. Find the speed of the boat in still water and the speed of the stream...
- The ratio of the speed of the boat in upstream to that of in downstream is 7:10, respectively. If the speed of the current is 12 km/h, then find the speed ...
Relevant for Exams:
