# Common work - 8th grade (13y) - math problems

1. Cable car
The cable car will carry 1280 passengers in 40 minutes. How many people will be transported in 2.5 hours?
2. The field
3 tractors plow the field in 6 hours. However, after 2 hours, 1 tractor broke down. How long will the field be plowed?
3. Work together
Two bricklayers plastering a wall. The first would plaster it in 8 hours, the second in 12 hours. How many hours will they be done with the work if they work together?
4. Five tractors
Five tractors plow the fields in 4.8 hours. How long will it take to plow the field when, after an hour and a half of work, two tractor drivers have been called up for another task?
5. The farmer
The farmer calculated that the supply of fodder for his 20 cows was enough for 60 days. He decided to sell 2 cows and a third of the feed. How long will the feed for the rest of the peasant's herd last?
6. The coal
The coal stock would be enough to heat a larger room for 12 weeks, a smaller one for 18 weeks. It was heated for four weeks in both rooms, then only in a smaller one. How long was the coal stock enough?
7. Digging
The first worker would dig a trench in 6 hours. For the second, the same work would take 4 hours. How long did it take for the trench to be dug if they worked together?
8. Bricklayers
The first bricklayer would build a wall in 3 days, the second in 4 days. The first bricklayer worked alone for a day, then the second bricklayer came to his aid and they finished the work together. How long did it take to build the wall?
9. Hectares of forest
12 workers plant 24 ha of forest in 6 days. In how many days will 15 people and 12 people plant the same area?
10. A lot of hay
Martin's grandfather weighed a lot of hay and calculated that for 15 rabbits it last in 100 days. How many days will this lot be enough for 25 rabbits?
11. Aircraft angines
The two engines of the aircraft are enough to supply the fuel for five hours of operation. However, one of the engines has a malfunction and thus consumes one-third more fuel. How long can the plane be in the air before it runs out of fuel? After an hour
12. Baking muffins
Aunt Polly is baking muffins at a speed of 4 muffins per minute. Tom comes into the kitchen when Aunt Polly has 12 muffins, and begins to eat these muffins at a speed of 6 muffins per minute. When he finally leaves the kitchen, there are 4 muffins at the
13. Panel house
The construction company has two groups of workers. Group A has more members than B. Panel house was insulated by group A in 10 days. The same block of flats was insulated together in 6 days. How many days would group B block insulate?
14. Temporary workers
Three temporary workers work in the warehouse and unload the goods in 9 hours. In what time would five temporary workers unload the same products?
15. Tributaries
The pool can be filled with two different tributaries. The first inflow would fill the pool in 18 hours, both in 6 hours. How many hours would the pool filled with a second inflow?
16. Two machines
The first machine can produce parts in 24 hours, the second in 16 hours. The first started working in the morning at 6:00 pm. Second at 10:00 o'clock. At what hour were all parts made?
17. Blueberries collecting
Marie collects blueberries 2 l in 1 hour. Began collecting at 8.00 pm, Joe collects 1.5 l in 1 hour. Peter 1 l for 1 hr. And they began to gather at 08.30 pm. Together they collect 10 l. At what time will they all have collected?
18. Six students
Two pupils painted the class in four hours. How long will it take for six pupils?
19. Blueberries
5 children collect 4 liters of blueberries in 1.5 hours. a) How many minutes do 3 children take 2 liters of blueberries? b) How many liters of blueberries will be taken by 8 children in 3 hours?
20. Two workers
One worker needs 40 hours to do a job, and the second would do it in 30 hours. They worked together for several hours, then the second was recalled, and the first completed the job itself in 5 hours. How many hours did they work together, and how much did

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