Math practice for 13 year olds - page 42 of 435
Number of problems found: 8682
- Price 11
The price increased from $2.56 to $3.76. What is the percentage increase?
- Iron ball 2
What is the mass of the iron ball with a diameter of 1,0 dm? The density of iron is 7870 kg/m³. .
- A triangle 7
A triangle lot has the dimensions a=15m, b=10m, and c=20m. What is the measure of the angle between the sides of b and c?
- A clock 2
A clock was set right at 6:00 AM. If it gains 3 1/2 minutes per hour, what time will it show at 6:00 PM on the same day?
- Hexagon, hexa S, V
What is the surface area and volume of a regular hexagonal prism with a base edge of 12cm and a height of the prism equal to the diameter of the circle circumscribed by the base?
- 216 surface area and volume
Calculate the surface area and volume of a regular tetrahedral pyramid: a = 6 cm and the body height is 12 cm.
- Pure gold
How much pure gold is in a 15-gram ring made of 14-carat gold? Round the result to the nearest tenth of a gram.
- Tractor 19
A tractor plows a field in 48 hours using a plow with 5 blades. How long will it take it to plow the same field with a plow with 6 blades of the same width, while maintaining the same tractor speed?
- Painting a column
How many kg of paint do we need to paint a column in the shape of a regular triangular prism with a base edge of 2.5 m long and a height to the base edge of 2 m, if 1 kg of paint is enough for 25 m² of paint? The column is 10 m high.
- Measuring cylinder
A measuring cylinder has a base radius of 35mm and a height of 500mm. Calculate the surface area wetted by the liquid if the level reaches a height of 35cm.
- Similarity coefficient
Given triangle ABC with sides a = 12 cm b = 9 cm c = 7 cm and triangle DEF with sides d = 8.4 cm, e = 6.3 cm f = 4.9 cm Find out if triangles ABC and DEF are similar if so, write the similarity coefficient and according to which sentence they are similar
- Women in the company
1467 women work in a factory. Women make up 46% of all employees in the factory. How many employees work in the factory?
- Water + temperature
We supplied 1365 kJ of heat to water weighing 5 kg and initially at 20°C. To what temperature did it heat up?
- Painters 5
Six painters were supposed to paint 6000 m² of area within the planned time. Two painters got sick, so each of the four who remained had to paint 50 m² more each day than the planned daily output. Calculate the original planned daily output of one painter
- John and Thomas
John and Thomas received 105 CZK from their grandmother together. John received one third more than Thomas. How many CZK did Thomas receive less than John?
- How big is 4
How big is the angle when one side is 20m and the other is 1.5m in a right triangle?
- In the library
We have 8 different books in the library. How many ways can they be arranged? How many possibilities are there if 3 volumes are to be in a certain order? How many possibilities are there if three volumes are to be in a row independently in order?
- Grass Mixture
Peter plans to buy a grass mixture consisting of meadow grass and fescue seeds for 40 euros. 1 kg of meadow grass costs 6 euros and 1 kg of fescue costs 10 euros. How much of each component should he buy if the resulting mixture is to weigh 6 kg?
- Waffle, bar
Jarmila bought a wafer, a bar, and a chocolate bar. She paid 38 Sk. The bar was 8 Sk more expensive than the wafer, and the chocolate bar was four times more expensive than the wafer. How much did the wafer, bar, and chocolate bar cost?
- Ice + water
A rectangular ice rink measuring 60 m by 30 m had a layer of ice 3 cm high. How many liters of water were used to create the ice?
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