Math practice for 13 year olds - page 75 of 422
Number of problems found: 8424
- Received 81440  At the flower festival, young growers sold cactus plants for CZK 12 and indoor violet plants for CZK 9. They sold a total of 47 pieces of flowers of both types and received CZK 501. How many cacti and how many violets did they sell? At the flower festival, young growers sold cactus plants for CZK 12 and indoor violet plants for CZK 9. They sold a total of 47 pieces of flowers of both types and received CZK 501. How many cacti and how many violets did they sell?
- Evaporating 81430  Sea water contains 3.4% salt. How much salt do we get by evaporating 25 kg of seawater, and how much water evaporates? Sea water contains 3.4% salt. How much salt do we get by evaporating 25 kg of seawater, and how much water evaporates?
- Produced 81413  A cube of sugar weighs 6 grams. How many sugar cubes are produced from one sugar beet that weighs 0.9 kg; if its sugar content is 18 percent? A cube of sugar weighs 6 grams. How many sugar cubes are produced from one sugar beet that weighs 0.9 kg; if its sugar content is 18 percent?
- Kilometers 81410  The tourist walked 1/4 of the way at a speed of 4.5 km/h, 2/5 at a speed of 4 km/h, and the remaining 7 km at a speed of 5 km/h. How many kilometers did he run, and how long did the journey take him? Calculate the time in a fraction. The tourist walked 1/4 of the way at a speed of 4.5 km/h, 2/5 at a speed of 4 km/h, and the remaining 7 km at a speed of 5 km/h. How many kilometers did he run, and how long did the journey take him? Calculate the time in a fraction.
- Calculate 81406  Calculate the equation and do the test. (x+6)/2 - (x+4)/4 = (2x+1)/3 – (x-4)/6 Calculate the equation and do the test. (x+6)/2 - (x+4)/4 = (2x+1)/3 – (x-4)/6
- Started 81404  At 7:30 AM, the bus left at a speed of 45 km/h, and at 8:00, a car behind it started at 65 km/h. Where and when did they meet? At 7:30 AM, the bus left at a speed of 45 km/h, and at 8:00, a car behind it started at 65 km/h. Where and when did they meet?
- Calculation 81402  In an isosceles triangle, the side a=b= 21 cm, and the triangle's height is 19 cm. Find out the base and perimeter of the triangle (sketch, calculation, answer). In an isosceles triangle, the side a=b= 21 cm, and the triangle's height is 19 cm. Find out the base and perimeter of the triangle (sketch, calculation, answer).
- Calculation 81401  A regular four-sided pyramid has a volume of 2,160 liters and a base edge length of 12 dm. Calculate the height of the needle (sketch, calculation, answer). A regular four-sided pyramid has a volume of 2,160 liters and a base edge length of 12 dm. Calculate the height of the needle (sketch, calculation, answer).
- Perimeters 81399  Two squares are given. The first has a side length of 5 cm, the second 10 cm. Write the ratio of: for a- of their sides for b- their perimeters for c- their areas Two squares are given. The first has a side length of 5 cm, the second 10 cm. Write the ratio of: for a- of their sides for b- their perimeters for c- their areas
- Notebooks 81398  Petr paid CZK 288 for 12 new notebooks. How much would he pay for 15 identical notebooks? Petr paid CZK 288 for 12 new notebooks. How much would he pay for 15 identical notebooks?
- If we want  A children’s pool has the shape of a cylinder with a base diameter of 4 m and a depth of 50 cm (sketch, calculation, answer). a) Calculate the volume of water in liters that can be in the pool if it is filled to the brim. b) If we fill the pool only 75%, A children’s pool has the shape of a cylinder with a base diameter of 4 m and a depth of 50 cm (sketch, calculation, answer). a) Calculate the volume of water in liters that can be in the pool if it is filled to the brim. b) If we fill the pool only 75%,
- Probability 81395  What is the probability that heads come up 5 times a row when tossing a coin? Write the result as a fraction. What is the probability that heads come up 5 times a row when tossing a coin? Write the result as a fraction.
- Vitamin doses  Children and adults take the recommended doses of vitamins daily throughout the year. According to the package insert, the recommended daily dose of vitamins for a child is half that of an adult. Two adults together consume one package of vitamins in 30 d Children and adults take the recommended doses of vitamins daily throughout the year. According to the package insert, the recommended daily dose of vitamins for a child is half that of an adult. Two adults together consume one package of vitamins in 30 d
- Advantageous 81389  The room has dimensions of 11 m x 5 m. Lino will be purchased for the room, which is sold in a roll with a width of 2 meters. How many meters of rope will be needed, and how much will be left? Consider both options for laying the line (lengthwise and widt The room has dimensions of 11 m x 5 m. Lino will be purchased for the room, which is sold in a roll with a width of 2 meters. How many meters of rope will be needed, and how much will be left? Consider both options for laying the line (lengthwise and widt
- Gradient of the railway  Calculate the gradient of the railway line, which has an elevation of 22.5 meters in a section of 1.5 kilometers. For railways, the result is given in h (per mille). Calculate the gradient of the railway line, which has an elevation of 22.5 meters in a section of 1.5 kilometers. For railways, the result is given in h (per mille).
- Quadrilateral 81385  A regular quadrilateral pyramid with base edge length a = 15cm and height v = 21cm is given. We draw two planes parallel to the base, dividing the height of the pyramid into three equal parts. Calculate the ratio of the volumes of the 3 bodies created. A regular quadrilateral pyramid with base edge length a = 15cm and height v = 21cm is given. We draw two planes parallel to the base, dividing the height of the pyramid into three equal parts. Calculate the ratio of the volumes of the 3 bodies created.
- Minutes 81382  The water barrel filled to 2/3 of its volume in 42 minutes. How long will it take to fill the barrel? The water barrel filled to 2/3 of its volume in 42 minutes. How long will it take to fill the barrel?
- Perpendicular parking  Which parking lot for 5 cars occupies a larger area, perpendicular or inclined at an angle of 45°, and how much? The car has dimensions of 4m and 2m. Which parking lot for 5 cars occupies a larger area, perpendicular or inclined at an angle of 45°, and how much? The car has dimensions of 4m and 2m.
- Friends 81380  In the lottery, where 326 numbers are drawn, Maros marked 7 numbers on the ticket. Kamil marked 11 numbers in another lottery, and 421 numbers were drawn. Which of these friends has a better chance of winning? In the lottery, where 326 numbers are drawn, Maros marked 7 numbers on the ticket. Kamil marked 11 numbers in another lottery, and 421 numbers were drawn. Which of these friends has a better chance of winning?
- Maximilian 81372  Tadeas the beetle set off from the house towards the cabbage leaf at a 20 m/min speed. Two minutes later, the Maximilian beetle followed him at 24 m/min speed. They both came to the cabbage leaf at the same time. How far was the letter from their house? Tadeas the beetle set off from the house towards the cabbage leaf at a 20 m/min speed. Two minutes later, the Maximilian beetle followed him at 24 m/min speed. They both came to the cabbage leaf at the same time. How far was the letter from their house?
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