Math practice for 13 year olds - page 58 of 435
Number of problems found: 8682
- Approximately 83106
The castle courtyard, with an area of 100 m², is paved with oak cubes with an edge of 8 cm. Approximately 164 bricks were used to pave m². One dm³ of oak wood weighs 0.8 kg. Calculate the weight of all the bricks used to pave the courtyard.
- Notebooks 83101
Jana bought 36 notebooks, three times as many with lines as with squares notebooks. Calculate how many lined notebooks she purchased.
- Airship
An airship is at a height x above the ground. Pavel watches it from point A at an elevation angle of 18 degrees 26 minutes. At the same time, Peter sees it from a small plane that is currently flying over Pavel at an altitude of 150m. Peter sees the airsh
- Solution 83099
There are spiders and flies on the window. They have a total of 38 legs. How many spiders and flies are there if a spider has 8 legs and a fly has 6? Just give one solution.
- Arithmetic 83094
There were 31 students in the class, and the arithmetic average weight was 43 kg. Calculate the average weight in the class if a student weighing 91 kg has been added to the class.
- Salt solution
The 50% salt solution must be diluted with distilled water to make 20 liters of 35% solution. How many liters of original solution and how many liters of water do we need?
- Dimensions 83092
On the 1:75 scale plan, the building plot is a rectangle with 60 cm and 50 cm dimensions. If 1 m² of land costs 80 euros, what is the price of the land?
- Jane bought
Jane bought several identical lined notebooks, several identical squared notebooks, and several identical compasses at a stationery store. Two lined notebooks and two squared notebooks cost a total of 180 crowns. Two squared notebooks cost the same as thr
- Determine 83083
A 6.5-meter-long ladder rests against a vertical wall. Its lower end rests on the ground 1.6 meters from the wall. Determine how high the top of the ladder reaches and at what angle it rests against the wall.
- Determine 83081
A paper kite is shaped like a deltoid ABCD, with two shorter sides 30 cm long, two longer sides 51 cm long, and a shorter diagonal 48 cm long. Determine the sizes of the internal angles of the given deltoid.
- Difference 83079
On the traffic sign that informs about the road's gradient, the figure is 6.7%. Determine the slope angle of the path. What height difference is covered by the car that traveled 2.8 km on this road?
- Penetrates 83078
A hammer with a mass of 600 g hits the head of a nail at a speed of 5 m/s. If the nail penetrates 3 cm into the wall, what is the average resistive force of the masonry?
- Overcoming 83076
A battering ram weighing 400 g falls from a height of 3 m. Upon impact, the stake hits a depth of 60 cm. What is the average force overcoming the soil resistance?
- Pages 83075
The book has 500 pages. Pepa has read half as many pages as he has left. How many pages did Pep read?
- Participating 83071
One hundred seventy-five school pupils signed up for the school trip. The ratio of boys to girls was 9: 16. In the end, 19 registered students did not come on the trip, so the ratio of the number of participating boys and girls was 9: 17. How many boys an
- Cylinder - curved area
The curved area of the rotary cylinder is three times greater than the area of one base of this cylinder. The radius of the base of the cylinder is 10 cm. What is the surface area of the cylinder?
- Simultaneously 83038
The cable car can take a given group of skiers out in 20 minutes and the lift in 30 minutes. How long will the lift and cable car take this group out simultaneously?
- 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?
- Concerning 83022
A man with a mass of 80 kg crosses at a speed of 5 m/s through the car of a train traveling at 15 m/s. Indeed, the kinetic energy of a man: and, concerning the car b, relative to the surface of the earth, if the man is traveling in the direction of travel
- 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
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