Maths practice for 12-year-olds - page 53 of 362
Number of problems found: 7228
- Kilograms 83037
8 kg of butter is made from 20 hl of milk. How many kilograms of butter can be made from 450 l of milk? - Centimeter 83033
Calculate the weight in kg of a steel rope 1.5 cm in diameter and 10 m long if one cubic centimeter of steel weighs 7.8 g - Determine 83021
Determine the kinetic energy of a car with a mass of 800 kg if it travels at a speed: a) 10 m/s b) 20 m/s - Horizontal 83020
What work must be done to bring a body of mass of 2 kg lying on a smooth horizontal plane from rest to a speed of 2 m/s? - Solution 83019
Kitchen vinegar is an 8% solution of acetic acid in water. How many liters of acetic acid are needed to produce 275 liters of vinegar? - Hamsters 83018
Jožko keeps dogs, guinea pigs, hamsters, and hares. A total of 24 animals. Of these, 1/3 are hamsters, 3/8 are guinea pigs, and 3/4 are not hares. How many dogs does Jožko have? - Corrects 83017
The new teacher corrects papers for 9 hours, and the older one fixes them in 6 hours. How much will they repair together?
- Arithmetically 83012
There were 21 pupils in the class, and arithmetically, the average height of these pupils was 163 cm. Calculate what the average height in the class will be if: a) A 159 cm tall student was added to the class b) A 169 cm tall student left the class - Copper 83011
Brass is an alloy of copper and zinc in a ratio of 3:2. How much copper and zinc do you need to make 1 kilo of brass? - Textbooks 83010
At 9 a.m., a truck with textbooks left Brno at a speed of 50 km/h; at 9:30 a.m., a passenger car left Brno with another delivery of textbooks at a speed of 70 km/h. When will the passenger car catch up with the truck? - Simultaneously 83009
A passenger train will travel from Brno to Bratislava (144km) in 3 hours; a freight train will cover this distance in 4.5 hours. How long will they meet if a passenger train from Brno and a freight train from Bratislava leave simultaneously? How many kilo - Statuette 83001
The bronze figurine weighs 0.5 kg. Bronze is an alloy of tin and copper in a ratio of 1:4. How many grams of copper and how many grams of tin does the statuette contain? - Squirrel 82999
A supply of acorns will last a squirrel for 12 weeks and a squirrel for 18 weeks. They ate acorns together for 4 weeks, then the squirrel left. How long did the squirrel have a supply of acorns? - Characters 82998
Adam wrote the following sum with five secret adders: a + bb + ccc + dddd + eeeee. He revealed that the characters "a, b, c, d, e" represent the different digits 1, 2, 3, 4, and 5 and that the resulting sum is divisible by 11. Which is the smallest and wh - Seedlings 82997
If you plant seedlings in the bed at a distance of 20 cm, 40 will fit here. How many seedlings will fit here if you reduce the distance between them to 15 cm?
- Remaining 82995
Children in the school club made a tricolor chain from crepe paper. One-eighth of the chain is red, three-quarters is olive, and the remaining 20 cm is blue. What length of chain did they make? - Expensive 82986
Mom bought three cakes at the pastry shop. The first cost 72 crowns. The second was a quarter cheaper than the first. The third dessert was a third of the total price of all three desserts. By how many crowns was the third dessert more expensive than the - Kangaroo 82979
A kangaroo can move at a speed of 65 km/h. How many minutes will it take to move at this speed to a place 6500 m away? - Capacity 82978
The pool has a maximum water capacity of 1200 hl. How many hours will the pool be half complete if the first inflow is 200 l per minute and the second 100 l per minute? - Marbles 82974
The bag has 5 red, 7 white, 10 yellow, and 6 black balls. At least how many marbles must be drawn from the bag to ensure that there will be 3 yellow ones among the drawn balls?
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