1. A horse eats a haystack in 2 days, a cow in 3 days, a sheep in 6 days. How long will it take a horse, a cow and a sheep to eat a haystack together?

2. The mill has three millstones. On the first one you can grind 60 quarters of grain per day, on the second - 54, and on the third - 48. Someone wants to grind 81 quarters of grain. In what shortest time can he grind the grain?

3.There were 300 buckets of water in the room. Two pumps began to pump out water. One pump pumps out 48 buckets in 2 hours, the other pumps out 129 buckets in 6 hours. How many hours will it take to pump out all the water if 8 buckets of water come from the ceiling every hour?

4. The tank holds 60 liters of water. Two pipes are connected to it. Through the first pipe you can fill an empty tank in 10 minutes. Through the second pipe you can empty a full tank in 15 minutes. How much water will be in the initially empty tank after 5 minutes if both pipes are opened?

5. Through the tap, water fills the tank in 3 hours, and through the drain hole, all the water from the tank is poured out in 5 hours. How long will it take for water to fill the tank with the tap and opening open? (Assume that the rate of water flowing out of the tank does not depend on its fullness.)

6. Sherlock Holmes and Dr. Watson working together can dig a ditch in 6 hours. If Holmes dug for 4 hours, and then Watson for 6 hours, the ditch would be 80% dug. How many hours would it take Holmes, working alone, to dig this ditch?

7. One snowblower could clear the entire street in 1 hour, and another in 45 minutes. Having started working simultaneously, the machines worked together for 20 minutes, after which the first one broke down. How many minutes did it take for the second machine to finish working?

8. In 3 and a half hours of operation, the first stamping press can produce 42% of all ordered parts. The second press can produce 60% of all parts in 9 hours of work. The speed of the third press is 20% higher than the speed of the second press. How long will it take to complete the entire order if all three presses are running simultaneously?

9. Three tractor teams worked together to plow the field in 4 days. The first and second brigades together would plow the same field in 6 days, and the first and third together in 8 days. How many times larger is the area plowed in three days by the third brigade compared to the area plowed in two days by the second brigade?

10. Ivan, Peter and Kirill were mowing the grass. Peter and Kirill would have mowed all the grass twice as fast as Ivan. Ivan and Kirill would have mowed all the grass three times faster than Peter. How many times faster than Kirill would Ivan and Peter mow all the grass?

11. Four little black little imps drew a drawing in black ink for four hours. If the first little devil drew twice as fast, and the second half as slowly, it would take them the same amount of time; if, on the contrary, the first one had drawn twice as slow, and the second twice as fast, then they would have finished it in two hours and forty minutes. How long would it take the first three imps to draw the drawing without the help of the fourth?

12. Three canal army men were digging a ditch. First, the first canal soldier worked half the time it took the other two to dig the entire ditch, then the second worked half the time it took the other two to dig the entire ditch, and finally the third worked half the time it took the other two to dig the entire ditch. As a result, the ditch was dug. How many times faster would the ditch be dug if all three had worked together from the very beginning?

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