Math practice for 13 year olds - page 58 of 429

Number of problems found: 8565

Cube pyramid volume
The cube ABCDEFGH has an edge of length 3 cm. Calculate the volume of the pyramid ABCDH.
Triangle height angle
Calculate the lengths of the sides in an isosceles triangle, given the height (to the base) Vc= 8.8cm and the angle at the base alpha= 38°40`.
Decoration
Jarka and Jana decided to decorate their common room. If Jarka painted it alone, it would take her 4 hours, and Jane 3 hours. How long would they paint the room if they painted together?
Cylinder axial section
The axial section of the cylinder is a square with an area of 56.25 cm². Calculate its surface area and volume. Express the result in square decimeters and cubic decimeters and round to hundredths.
Triangle angle sizes
In triangle ABC, the internal angle beta is twice the size of the angle alpha, and the angle gamma is 20 degrees less than the size of the angle beta. Determine the size of all interior angles of this triangle.
Gram price euros
If 5000g costs €120, how much will 100g cost?
Basket pom market
During the first two days of the Easter market, the basket maker sold all the knitted pom poms; on the first day, he sold a fifth of all pom poms. On the second day, he sold 180 more pom poms than on the first day. How many pomelos did the barber sell on
Boys book pages
Three boys, Ivo, Vlado, and Alan, are reading the same book, with the condition that they will read the same number of pages every day during the entire reading until they finish the book. Ivo reads 18 pages from it every day, Vlado reads 24 pages, and Al
Iron bar weight
Calculate the weight of an iron bar 1.2 m long, whose cross-section is a trapezoid with dimensions a=10 cm c=8 cm and the distance between the bases v=6 cm. As we know, 1 cubic meter of iron weighs 7800 kg.
Paint mixture ratio
A painter needs to mix yellow and red paint in a ratio of 3:7. How many liters of red paint must he add to 21 liters of yellow paint?
Tractor field percentage
The tractor operator plans to plow a 24 ha (ha=hectare) field. He already plowed 20.64 ha. What percentage has he already fulfilled the plan?
Plot plan scale
The square-shaped plot actually covers an area of 81 ares. Maybe draw it in the village plan on a scale of 1:200. What will be the length of the side on the plan?
In a queue
There are cars and trucks in a queue in front of a toll gate. A truck is three times longer than a car. Calculate how many cars are in front of the car that has just arrived, if there is one truck among them, which is one eighth of the length of the queue
Water temperature cooling
We have 160 L of water at 67°C; how many liters of cold water at 18°C are needed to cool it to 39°C?
Dirty fuel - coal
Coal for 15 families lasts 60 days. How many days will the coal last for 20 families?
Triangle construction progress
An isosceles triangle ABY has a base AB of length 5 cm and an angle at the primary vertex of 50°. Write down the construction progress.
Workers 4
Workers in a workshop machined the same parts for three months. Their output increased so that each subsequent month they machined 10 percent more parts than the previous month. In the last month, they machined 484 parts. How many parts did they machine i
Bell copper tin
Nine kilograms of bell metal contain 7 kg of copper, the rest of which is tin. How much copper and how much tin were used to cast five bells? Each of the two larger bells weighed 535kg, and each of the remaining three smaller ones weighed 286kg.
Bronze copper tin
Bronze is an alloy of copper and tin in a ratio of 1:4. How much copper does a bronze piece of jewelry weighing 25 g contain?
Buy and sell
The selling price is 5.75 EUR, and the buying price is 4 EUR. By what percentage was the price increased?

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