1. The speed of the current is 5 km/h. A boat goes 10 km upstream and back again to the starting point in 50 min. Find the speed of the boat in still water.
2. In a fixed time, a boy swims \(\frac{5}{2}\) times the distance along the current that he swims that he swims against the current. If the speed of the current is 6 km/h. Find the speed of the boy in still water.
3. The speed of a motor boat in still water is 60 km/h. If the motor boat travels 90 km along the stream in 1h 7min 30sec, then find the time taken by it to cover the same distance against the stream.
4. Two boats A and B start towards each other from two places, 112 km apart. Speed of the boat A and B in still water are 8 km/h & 14 km/h respectively. If A proceeds downstream & B proceeds upstream then after how much time they will meet ?
5. A person can row 12 km/h in still water and he finds that it takes him twice as long to row up as to row down the river. Find the speed of the stream.
6. A boat goes 42 km upstream in 7 hours and 40 km downstream in 5 hours. Find the speed of the boat in still water.
7. A man can row at a speed of 18 km/h in still water. If he takes 2 times as long to row a distance upstream as to row the same distance downstream then find the speed of the stream.
8. The speed of a motor boat to that of current of water is 30 : 7. The boat goes along the current in 4h 36 min. Find the time when it will come back ?
9. The speed of a boat in still water is 8 km/h and the speed of the stream is 3 km/h. A man rows to a place at a distance of 41.25 km and comes back to the starting point. Find the total time taken by him.
10. If the speed of boat in still water is 5 km/h and upstream speed is 3 km/h. Find the speed of the current.
11. A boat moves with a speed of 13 km/h downstream and 7 km/h upstream. Find the speed of the boat and stream.
12. A man can row 45 km upstream and 66 km downstream in 15 h. Also, he can row 65 km upstream and 77 km downstream in 20 h. Find the speed of man in still water & rate of current.
13. A motorboat went downstream for 32 km and immediately returned. It took the boat twice as long to make the return trip. If the speed of the river flow were twice as high, the trip down stream and back would take 768 minutes. Find the speed of the boat in still water and the speed of the river flow ?
14. A boat sails downstream from point A to point B, which is 20 km away from A and then returnes to A. If the actual speed of the boat (in still water) is 3 km/h, the trip from A to B takes 5 hours less than that from B to A. What must be the actual speed of the boat for the trip from A to B to take exactly \(\frac{{400}}{3}\) min.
15. In a stream, B lies in between A and C such that it is equidistant from both A and C. A boat can go from A to B and back in 9.2 h while it goes from A to C in 12 h. How long would it take to go from C to A ?
16. A, B, C are three town on a river which flows uniformly. B is equidistant from A & C. Amit can row A to B and back in 10ᵗʰ and he can row from A to C in 6ᵗʰ. Compare the speed of his boat in still water with that of the river ?
17. The speed of a boat in still water is 9 km/h. A boat goes 64 km and back to its starting point in 16 hours. find the speed of the stream.
18. The normal speed of a boat in still water is 5 times the speed of the river. The boat goes upstream from A to B and takes 3 h to reach B. By what percent should the boat increase/decrease its speed if it reaches from B to A downstream in 4 h.
19. The ratio of time taken by a boat to row a certain distance downstream, and upstream is 4 : 7. If the speed of current is \(2\frac{2}{{11}}\) km/h then what is the speed of boat in still water.
20. A motorboat moves from point A to point B and back again. If the speed of the boat in still water is doubled, then the trip from A to B and back again would take 33.33% of the time that the motorboat usually spends in the journey. How many times is their actual speed of the motorboat higher than the speed of the river flow.
21. A was travelling in his boat, when the wind blew his hat off and the hat started floating back downstream. The boat continued to travel upstream for 15 more minutes before A realized that his hat had fallen off and turned back downstream. He caught up with that as soom as it reached the starting point. Find the speed of the river if A’s hat flew off exactly 5 km from where he started.
22. A boat goes 40 km and back to starting point in 8 h. The time taken by the boat to row 4 km downstream is equal to the time taken by the boat to row 3 km upstream. Find the speed of boat in still water and the rate of current.
23. The speed of 30 m long motor boat in still water is 32 km/h. This motorboat is moving in the river whose speed is 5 km/h. Travelling upstream it crosses a temple situated at the bank of river in 10 seconds. Find the length of the temple.
24. A boat rows downstream 68 km and upstream 45 km in 9 hours. The same boat rows 51 km downstream & 72 km upstream in 2 hours more. Find the rate of current and the speed of the boat in still water.
25. A ship is 126 km from the shore, springs a leak which admits 3.5 ton of water every 7 minute. An outlet tank can through out 18 tons of water per hour. Find at what speed it should move such that when it begins to sink a rescue ship moves with 8 km/h escapes the passengers of the ship, if 84 ton of water is enough to sink ?
26. Two boats go downstream from point A to point B. The faster boat covers the distance from A to B \(1\frac{1}{4}\) times as fast as the slower boat. It is known that for every hour the slower boat lags behind the faster boat by 10 km. However if they go upstream then the faster boat covers the distance from y to x in half the time as the slower boat. Find the speed of the slower boat in still water.