Math practice for 13 year olds - page 60 of 419
Number of problems found: 8372
- What quantity 
 What quantity of concrete should be ordered for concreting a rectangular family house with dimensions of 15 m × 12.6 m using permanent formwork? The depth of the foundation formed by permanent formwork is set at 80 cm. The concrete used constitutes 80% of - Percentage 82856 
 By what percentage is the number 15 different from the number 12? - Against 82851 
 A 3.4 m long ladder is leaning against a wall. Its lower end is 1.6 m away from the wall. At what height does the ladder touch the wall? - Diagonals 82850 
 How do I find the diagonals of a rhombus if its perimeter is 80dm and one diagonal is 2x larger than the other? - Linnaeus 82847 
 The cook bought 54 desserts for each of the diners and paid 14.35 Euros for them. Creams were 0.30 Euro each, and Linnaeus cakes were 0.25 Euro each. How many creams and how many Linnaeus cakes did she buy? - Dimensions 82810 
 The block has 10 cm, 20 cm, and 50 cm dimensions. We reduce the first edge of the cuboid by 20% and increase the second by 20%. How does the volume of the cuboid change? By how many percent? - Calculate 82808 
 Calculate the radius of an iron ball with a density of 7.8g/cm³ and a mass of 7kg. - Cashier 82807 
 To pay out the amount of CZK 570, the cashier used 15 coins: a few fifty crowns and a few twenty crowns. How did she pay the amount? - Open simultaneously 
 An empty tank is filled with inflow in 30 minutes. A full tank is emptied in 75 minutes with an open drain. How long does it take for an empty tank to fill up if both the inlet and outlet are open simultaneously? - Elevation angle 
 An airliner currently flying over a location 2,400 m away from the observer's location is seen at an elevation angle of 26° 20'. At what height does the plane fly? - Workers 82802 
 Five workers do a job in 20 hours. How long will it take two workers to do the same job? - Accumulator 82755 
 The battery capacity is 50 Ah. With a current of 5A, we charge the accumulator to 100% capacity in 10 hours. To what percentage of capacity can we charge the accumulator with a current of 2A in 15 hours? - Justify 
 50 bottles of red wine are purchased for a company party. In the first store, a bottle of wine costs €6.90. Here they have a promotion that when you buy 4 bottles, the fifth one is free. In the second store, the same bottle of wine costs €8.50. However, t - Overtake 82752 
 I am passing a tractor whose speed is 20 km/h. The length of the tractor with the siding is 10 m. My speed is 50 km/h. How long will I overtake the tractor? - Intervention 82748 
 The missile flies towards the plane at a 2000 km/h speed. The speed of the plane is 1000 km/h. The intervention is after 1.5 minutes. How far apart were the rocket and the aircraft in the beginning? - Quadrilateral pyramid 
 Construct a 3D model of a quadrilateral pyramid with a rectangle base and sides of isosceles triangles, with a volume of 80 cubic cm. I need to know the sides and the height. - Children's 82745 
 The children's car has wheels with a radius of 15 cm, and its speed is 36 km/h. How many times does the toy car wheel turn in a minute at this speed? - Branches 82741 
 The meadow has massive trees, a lake, and tall grass. A seventh of the birds sit in nests in trees. A third swim in the lake and a quarter of the birds sit in nests in the tall grass. Twenty-three birds are sitting on tree branches. How many birds are the - Containers 82736 
 Two filling machines fill 250 containers in 2 hours. How many containers will 4 machines fill in 3 hours? - Kilometers 82735 
 Fifteen kilometers in front of us, a car travels at a speed of 70 km/h. We drive at an average speed of 100 km/h. How many minutes will it take us to catch up with the car? 
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