Maths practice for 12-year-olds - page 315 of 351
Number of problems found: 7008
- Mouse Hryzka
Mouse Hryzka found 27 identical cubes of cheese. She first put a large cube out of them and then waited for a while before the cheese cubes stuck together. Then, she will eat the middle cube from every wall of the big cube. Then she also eats the cube in
- Diameter
The diameter of a circular plot is 14 dm. Find the circumference and area.
- Tank
How many minutes does it take to fill the tank with 25 cubic meters of water filled at 150 hl per hour?
- Tetrahedral prism
The height of a regular tetrahedral prism is three times greater than the length of the base edge. Calculate the length of the base edge if you know that the prism volume is 2187 cm³.
- Grandmother's clocks
Grandmother's clock is half a minute late every hour. Grandmother set the clock exactly at 8.00 AM. How many hours will show after 24 hours?
- Children
Margaret and Zdena weigh the same, and Petra weighs 3 kg more. Together, they weigh 156 kg. How much do they weigh?
- New computer
The new computer processes a certain amount of data for 6 hours. How many hours will an older computer with a quarter lower performance process the same amount of data?
- Cube 8
The surface of the cube is 0.54 m². Calculate the length of the cube edge.
- Trip
On the trip drank 3/10 of pupils tea, 2/5 cola, 1/4 mineral water, and the remaining three juice. How many students were on the trip?
- Construct 1
Construct a triangle ABC, a = 7 cm, b = 9 cm with a right angle at C, and construct the axis of all three sides. Measure the length of side c (and write).
- The pot
The diameter of the pot is 38 cm. The height is 30 cm. How many liters of water can fit in the pot?
- Ships
The red ship begins its circuit every 30 minutes. The blue boat begins its circuit every 45 minutes. Both ships begin their sightseeing circuit in the same place at the same time, always at 10:00 o'clock. a / What time does the boat meet again? b / How ma
- Rectangle - parallelogram
A rectangle is circumscribed by a circle with a radius of 5 cm. The short side of the rectangle measures 6 cm. Calculate the perimeter of a parallelogram ABCD, whose vertices are the midpoints of the sides of the rectangle.
- Videotape
Viera bought a videotape on which she could record programs with a total length of 240 minutes. She recorded a sci-fi movie, 1 hour and 28 minutes long, five ten-minute sessions, and "aerobics at home." Can she fit on the tape even the film of Robin Hood,
- The port
Four ships Berthed in the port. Together, sail from a port. The first ship will return to port every two weeks, the second after four weeks, the third after eight weeks, and the fourth after 12 weeks. After how many weeks do all the boats meet at the port
- TVs
Production of television sets increased from 3,500 units to 4,200 units. Calculate the percentage of production increase.
- Minutes
Determine the difference in minutes: T1 = 2 3/20 h T2 = 2.3 h
- Cube 5
The surface of the cube is 15.36 dm². How will this cube's surface area change if the edges' length is reduced by 2 cm?
- Metal sheet
The box has the shape of a cube with an edge length of 50 cm. How much m² of sheet metal is needed to beat a box if we add 20% on the folds of the lid and walls?
- Nectar
Nectar collected by bees contains 70% water. The nectar of the same process produces honey which has 19% water. How many kilograms of nectar do bees need to collect to make 1 kg of honey?
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