Math practice for 13 year olds - page 319 of 423
Number of problems found: 8458
- Pyramid Z8–I–6
Each brick of the pyramid contains one number. Whenever possible, the number in each brick is the lowest common multiple of two numbers of bricks lying directly above it. May that number be in the lowest brick? Determine all possibilities. - Circumference 4532
The block ABCDEFGH is given, / AB / = 3.5 cm, / BC / = 4.1 cm, and the circumference of the BCGF wall is 12.4 cm. Calculate the block's area and volume. - Cube 1-2-3
Calculate the volume and surface area of the cube ABCDEFGH if: a) /AB/ = 4 cm b) The perimeter of wall ABCD is 22 cm c) the sum of the lengths of all cube edges is 30 cm. - Distances
A boy is rowing a boat at a speed of 7.2 km/h. He directed the boat perpendicularly to the opposite bank, which is 600 m away. The river carries the boat at a speed of 4.0 km/h. What is the resulting speed of the boat relative to the bank? How far will th - Preserve 4528
Mom bought one tin of beef and two pies for dinner. She paid a total of CZK 41 for it. Another lady bought two canned beef and five pates and paid CZK 88. How many kroner does a preserve cost, and how much pate? - Distance 4527
There are two points, K and L, KL = 4 cm. Draw a line p passing through point K and having a distance of 4 cm from point L. - Lump sugar
Cubed sugar in a 1 kg package is in a box with 20 cm, 12 cm, and 5 cm dimensions. a) How many sugar cubes with dimensions 2.5 cm, 2.5 cm, and 1 cm fit in the box? b) Calculate the mass of one cube. c) How many square meters of cardboard are needed to make - Ten-liter 4524
3 mm of water rained down on the garden with an area of 800 m². How many ten-liter cans did this rain replace? - Rectangle 4523
How high must the box, the bottom of which is a rectangle with sides of 40 cm, 625 mm, have a volume of 1 hl? - Trees
A young tree is 16 inches tall. One year later, it is 20 inches tall. What is the percent increase in height? - 2d shape
Calculate the area of a shape in which an arbitrary point is not more than 3 cm from the segment AB. The length of segment AB is 5 cm. - Rectangle 3-4-5
The sides of the rectangle are in a ratio of 3:4. The length of its diagonal is 20 cm. Calculate the area of the rectangle. - Passenger 4513
From two cities, A, and B, 210 km apart, two cars left at the same time at 8:00 AM opposite each other. A truck left place A at a speed of 60 km/h, and a passenger car left place B at 80 km/h. At what time did the cars meet? - Vehicle tank
A vehicle tank was 3/5 full of petrol. When 21 liters of fuel was added, it was 5/6 full. How many liters of petrol can the tank hold? - Cross-section 4507
How much soil needs to be removed when digging a 200 meter long ditch whose cross-section is an isosceles trapezoid with an area of 4812.5 cm²? - Regular n-gon
Which regular polygon has a radius of circumscribed circle r = 10 cm and the radius of inscribed circle p = 9.962 cm? - Harvesters 4498
The first combine harvester will harvest the fields in 12 hours, and the second combine harvester in 8 hours. How long does it take for the same harvester to harvest the 3rd combine if all three harvesters harvest together in 2 hours? - Average speed
When the bus stops at a bus stop, the average speed is 45 km/h. It would drive at 54 km/h if it did not stop. How many minutes of every hour does it spend at stops? - Obtained 4484
25% oil is obtained from one flaxseed. From how many kg of flax seeds is 1.5 kg of oil obtained? - Aircraft 4480
Two planes take off simultaneously from airports A and B, fly towards each other, and meet in 20 minutes. The distance between the airports is 220 km, and the average speed of the aircraft flying from airport A is 60 km/h more than the average speed of th
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