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Infringement complaint

Twelve, the problem of running water (volume A)

Downstream = Ship Speed + Water Speed

Counterflow = Ship Speed-Water Speed

Ship speed = downstream + countercurrent / 2

Water speed = downstream-countercurrent / 2

Speed = distance / time

I. Fill in the blanks

1.The ship travels in a section of a river of 120 kilometers long, and it uses 10 Xiaoming to go up the current, and 6 hours to go down, the water speed is _______, and the ship speed is ________.

2.A boat goes up against the current, with a water speed of 2 kilometers, a boat speed of 32 kilometers, and a ________ kilometers for 4 hours. (Ship speed, water speed is calculated per hour)

3.A boat travels 8 kilometers per hour in still water, and travels 12 kilometers in reverse for 2 hours at a speed of ________.

4. The speed of a ship in still water is 18 kilometers per hour, and the water speed is 2 kilometers per hour. This boat needs 15 hours to travel from A to B to backwater, so the distance between A and B is _______ thousand. Meter.

5.The two docks are 192 kilometers away. It takes 8 hours for a motorboat to travel down the water. It is known that the speed of the water is 4 kilometers per hour, and it takes ________ hours to complete the travel against the water.

6.The two docks are 432 kilometers away, and the steamer will travel 16 hours along the water. The headwater will travel 9 kilometers less per hour than the water, and it will take more ________ hours than the water.

7. River A is a tributary of River B. The speed of water in River A is 3 kilometers per hour, and the speed of water in River B is 2 kilometers. A boat sails along River A for 7 hours and travels 133 kilometers to River B. In the B river, it will sail 84 kilometers against the water, and this boat will travel for _______ hours.

8.A and B ships head up from the port A. The A ship travels 15 kilometers per hour in still water, the B boat travels 12 kilometers per hour, and the water speed is 3 kilometers per hour. The ship just started to leave. When ship A caught up with ship B, it had left port A ______ kilometers.

9. It is known that for the 80 km waterway, it takes 4 hours for boat A to go down and 10 hours for upstream. If boat B takes 5 hours to go downstream, it will take _______ hours for boat B to go upstream.

10. It is known that 60 kilometers from the place A in the river to Haikou, if the boat goes down the river, it can reach Haikou in 4 hours. The water speed is known to be 6 kilometers per hour. The water speed from the sea to the river is 3 kilometers per hour.It will take another ______ hours for the ship to return to its place.