Math practice for 13 year olds - page 48 of 422
Number of problems found: 8424
- Spiral - iron  An electric iron is connected to a 230 V voltage source. Its heating coil has an electrical resistance of 100 ohms. Calculate the power of the iron and the electric current flowing through the coil. An electric iron is connected to a 230 V voltage source. Its heating coil has an electrical resistance of 100 ohms. Calculate the power of the iron and the electric current flowing through the coil.
- Tank 28  The tank fills in 120 hours. When irrigated, it empties in 10 days. At what time will it fill with simultaneous irrigation? The tank fills in 120 hours. When irrigated, it empties in 10 days. At what time will it fill with simultaneous irrigation?
- Oranges and apples  Mr. Novák bought 5 times more oranges than apples. One orange cost 8 CZK and one apple costs 12 CZK. He paid 156 CZK in total. How many oranges and apples did he buy? Mr. Novák bought 5 times more oranges than apples. One orange cost 8 CZK and one apple costs 12 CZK. He paid 156 CZK in total. How many oranges and apples did he buy?
- Asphalt  A tennis court can have a grass, asphalt, or clay surface. Singles are played on a court 23.78 m long and 8.23 m wide. For doubles, a strip 1.37 m wide is added on both longer sides. How many m² is a tennis court for doubles larger than for singles? A tennis court can have a grass, asphalt, or clay surface. Singles are played on a court 23.78 m long and 8.23 m wide. For doubles, a strip 1.37 m wide is added on both longer sides. How many m² is a tennis court for doubles larger than for singles?
- Railing 3  A railing in a museum is filled with 18 glass plates in the shape of a parallelogram with a side length of 40cm and a corresponding height of 65cm. How many m² of glass were needed to produce these fillings? A railing in a museum is filled with 18 glass plates in the shape of a parallelogram with a side length of 40cm and a corresponding height of 65cm. How many m² of glass were needed to produce these fillings?
- Expanding  A problem has spread here - money printing. The ECB claims it aims to maintain a price level with 2% inflation. But for the last three years in a row, annual inflation has been 6%, 7% and 9%. A problem has spread here - money printing. The ECB claims it aims to maintain a price level with 2% inflation. But for the last three years in a row, annual inflation has been 6%, 7% and 9%.
- Divisible PIN  Marek's mother helped him with his shopping. She wanted to pay with a card when collecting the goods in person, but she wasn't sure what her PIN was. Could it have been if her PIN code was a number divisible by six? Marek's mother helped him with his shopping. She wanted to pay with a card when collecting the goods in person, but she wasn't sure what her PIN was. Could it have been if her PIN code was a number divisible by six?
- Triangles - combinations  How many different triangles with sides in whole centimeters have a perimeter of 12 cm? How many different triangles with sides in whole centimeters have a perimeter of 12 cm?
- Determine 23  Determine in cm² the area of the rectangle ABCD, whose longer side a=20cm and whose diagonal is 10cm longer than its shorter side. Determine in cm² the area of the rectangle ABCD, whose longer side a=20cm and whose diagonal is 10cm longer than its shorter side.
- Wall and ladder  A ladder is leaning against a wall at a height of 6.5 m. How long is the ladder if it makes an angle of 60° with the horizontal floor? A ladder is leaning against a wall at a height of 6.5 m. How long is the ladder if it makes an angle of 60° with the horizontal floor?
- Production  The company's production in February was 15% greater than in January and 25% less than in March. By what percent was the production in March higher than in January? The company's production in February was 15% greater than in January and 25% less than in March. By what percent was the production in March higher than in January?
- Isosceles gable  The roof of a cottage has a gable in the shape of an isosceles triangle with a base length of 8m and a side length of 10m. How high is the gable? The roof of a cottage has a gable in the shape of an isosceles triangle with a base length of 8m and a side length of 10m. How high is the gable?
- Diagonal 2  What is the area in square meters of a rectangular garden whose diagonal is 50m long and the width of the garden is 27m? Round the result to the nearest whole number. What is the area in square meters of a rectangular garden whose diagonal is 50m long and the width of the garden is 27m? Round the result to the nearest whole number.
- Acceleration of a car  What was the initial speed of the car when, after accelerating 2 m/s², it gained a speed of 30m/s in 10 seconds? What was the initial speed of the car when, after accelerating 2 m/s², it gained a speed of 30m/s in 10 seconds?
- Acceleration - free fall  How long will it take for a car to reach speed of 180 km/h with an acceleration of 10 m/s²? How long will it take for a car to reach speed of 180 km/h with an acceleration of 10 m/s²?
- Rhombus - ratio  In a rhombus, the ratio of the side to the height to this side is 4 : 1, if its area is 49 cm². Calculate the size of the side and the height to this side. In a rhombus, the ratio of the side to the height to this side is 4 : 1, if its area is 49 cm². Calculate the size of the side and the height to this side.
- Swimming pool 5  There are 5500 men, women, and children at the swimming pool. There are twice as many women as men and four times as many children as women. How many men, women, and children are there at the swimming pool? There are 5500 men, women, and children at the swimming pool. There are twice as many women as men and four times as many children as women. How many men, women, and children are there at the swimming pool?
- Hypotenuse 84015  In a right triangle ABC, the hypotenuse c = 8 cm and the side b = 4 cm. What is the size of angle α? In a right triangle ABC, the hypotenuse c = 8 cm and the side b = 4 cm. What is the size of angle α?
- What is 19  What is the length of the hypotenuse c of a right triangle ABC if the angle α at vertex A is 30° and the hypotenuse a = 3cm? What is the length of the hypotenuse c of a right triangle ABC if the angle α at vertex A is 30° and the hypotenuse a = 3cm?
- In a right-angled 15  In a right-angled triangle ABC with hypotenuse c, the length of the side b = 4.5 cm and tan α = 2/3. What is the length of the side a? In a right-angled triangle ABC with hypotenuse c, the length of the side b = 4.5 cm and tan α = 2/3. What is the length of the side a?
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