Common work - 7th grade (12y) - math problems

  1. The farmer
    cow 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?
  2. The orchard
    jablone 4 temporary workers harvested the orchard in 9 days. How many temporary workers we need for six days?
  3. A lot of hay
    zajic 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?
  4. Grandma
    zemiaky 6 kg of potatoes is enough for four at home for 15 days. For how many days will this amount be enough if a grandma will visit?
  5. Tributaries
    inlets 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?
  6. Two machines
    clock-night-schr_1 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?
  7. Blueberries collecting
    blueberry_1 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?
  8. Painters
    time Ten painters paint the school in 20 days. How many days do four painters paint the school at the same pace of work?
  9. Cook on gas
    lpg The gas cylinder will last for 30 weekends for 2 hours of daily cooking. How many days will we be able to cook on a new cylinder when we cook 3 hours a day?
  10. Four workers
    wood_6 Four workers will lay the floor of the gym in six hours. After an hour of working together, one of the workers left to the doctor. How long before the remaining three workers finish their work?
  11. Lumberjacks
    stromy_17 Fifteen lumberjacks would take 12 days to destroy the broken trees. How many days would this work require if 5 workers added to it after 4 days?
  12. Flowerbed
    flowers_9 Ondra digs the bed in 20 minutes. Cuba in 30 minutes. For how long do they dig together?
  13. Inlet minus outlet
    inlets_6 Water flows into the tank through two pipes and flows out of the third pipe spontaneously. The pipe A itself would fill the tank in 3 hours, the pipe B itself would fille in 4 hours, and the pipe C itself would flow out in 12 hours. How long will the tank
  14. Pumps
    pumps_8 After the floods, four equally powerful pumps exhausted water from the flooded cellar in 6 hours. How many hours would take a drained out with three equally powerful pumps?
  15. Construction of road
    truck_14 For the construction of the road dam, it is supposed to transport six trucks a total of 18 days. After three days, two more cars were sent to the construction site. How long will it take to carry the material?
  16. Hay bags
    krav 4 cows eat 16 hay bags in 5 days. How many bags will eat 5 cows in 7 days?
  17. Two workers
    clock-night-schr_12 The first worker would himself completed the work in 8 hours, the other in 6 hours. After two hours of joint work left the first worker to a doctor and other completed work himself. How many hours worked the other worker himself?
  18. The factory
    clocks_13 The factory z can complete an order in 12 days, factory p in 18 days. For how many days does an order completed when the first two days work only the factory z and then both factories?
  19. Harvesters
    kombajn_10 The first harvester will harvest the grain from the field in 20 hours, the second, the more powerful in 10 hours. How long will take harvest this field by both harvesters, if the second harvester has to be set up first and this takes 2 hours? The first ha
  20. Inlet and outlet
    bazen2_19 The pool has a capacity of 50 hl. The inlet pipe flows in 1 minute 1.25 hl, and the waste pipe outlet is draining the full pool in 50 minutes. How long will take the empty the full pool when both the inlet and outlet are opened at the same time?

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