Examples of equations for practice for 13 year olds - page 40 of 98
Number of problems found: 1959
- Solution 19283
How many grams of 80% solution and 55% solution do we need to mix to obtain 100 grams of 60% solution? - Children 18963
There are 39 people on the bus. There are 11 more adults than children. How many children are on the bus, and how many adults? - Mushrooms 18933
When dried, mushrooms lose 80% of their weight. How many fresh mushrooms do we need to get half a kilogram of dried ones? - Unknown 18893
The number 290 is 16% larger than the unknown number. What's the unknown number?
- Bricklayers 18773
According to the standard, we calculated that two masons would plaster the corridor of the new school building in 54 hours. How long would it take for nine bricklayers to plaster this corridor? - Consumption 18743
With the consumption of 0.4 t of coal per day, the supply lasts for 36 days. How many days will the supply be enough if 16 kg of coal is used less daily? - Gibraltar 18553
The length of the Strait of Gibraltar is 1.5 times the length of the Bering Strait. The total length of both straits is 150 km. Find the length of each waterway. - Branches 18533
The right triangle has an area of 225 cm². One of its branches is twice the size of the other. Find the lengths of its hangers. - Reducing
Reducing the unknown number by 427, we get 65% of its value. What is an unknown number?
- Machine 18483
Coins worth 20 cents and 50 cents are thrown into a coffee machine. There are 199 coins in the machine with a total value of € 68. How many are 20-cent coins in the machine? - Fifteen 18403
Fifteen ants bring 10 g of food to the anthill in 1 hour. In how many hours will five ants carry 1 kg of food? - Approximately 18133
Mr. Kotek drove from Brno to Prague at 11 a.m. at a speed of 80 km/h. His friend drove from Prague to Brno half an hour later at a speed of 85 km/h. Which of them will be closer to Prague when they meet? The distance between the cities is approximately 21 - Consecutive 18083
The sum of five consecutive even numbers is 40. Find these numbers. - Heavy-duty 17941
The railroad workers carried five loads with five heavy trains than ten standard trains. What is the weight of a heavy-duty train if it is 2,200 t heavier than a standard train?
- Double-performance 17931
Excavation work was carried out by nine double-performance machines, which excavated 420 meters of excavation in one day. How many were there if the more powerful machine excavated 420 meters in a week (7 days) and the less powerful engine excavated 280 m - Simultaneously 17821
The reservoir is filled with the first pump in 30 hours, the second in 24 hours, and the third in 20 hours. How long does it take to fill the reservoir if all pumps are switched on simultaneously? - Twenty-eight 17673
Twenty-eight children participated in the Pythagorean school round. The number of children who ranked only behind Rasťo was twice as large as the number of children who were more successful than Rasťo. How many places did Rasťo finish? - Twelve ties
The price of 12 ties before the discount was the same as 15 ties after the discount. Calculate the price of 1 tie after the discount if you know that the discount price of one tie fell by 40 CZK. - Harvested 17623
The farmer managed to increase wheat yield per hectare by 0.4 tons by improving the soil, so he harvested 140 tons of wheat from 25 ha. What was the original yield per hectare? Please round the result to one decimal place.
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