Math practice for 13 year olds - page 237 of 413
Number of problems found: 8260
- Metal tube
Calculate the metal tube mass 8 dm long with an outer radius of 5 cm and an inner radius of 4.5 cm. One cm³ of this metal is 9.5 g. - Winch
The steel rope has a diameter of 6mm and a length of 20m. We are winding it on a drum width of 60 mm, with a starting diameter of 50 mm. What is the final diameter after winding? - Delayed clock
Michael put a new battery into his watch at midnight. However, they are 5 seconds late each minute. How many hours does the watch show in 24 hours? - Iceberg
What is the surface area of a 50 cm iceberg (in the shape of a cuboid) that can carry a man with luggage with a total weight of 120 kg? - Banknotes
How many different ways can the cashier pay out € 310 if he uses only 50 and 20 euro banknotes? Find all solutions. - Concentric circles
There is given a Circle K with a radius r = 8 cm. How large must a radius have a smaller concentric circle that divides the circle K into two parts with the same area? - Assembly parts
Nine machines produce 1,800 parts on nine machines. How many hours will it produce 2 100 parts on seven such machines? - Seven workers
Seven workers clear the glade in 22 hours. How many workers would be needed to complete the task in 8 hours? - Cylinder in a Cube
The cube has an edge length of 5 cm. This cube surrounds a rotating cylinder. Find the surface area of the shell and the volume of the cylinder. - Bed 10
A bed in the shape of two equilateral triangles sharing a common side, with a side length of 2.5 m, is to be planted with seedlings of an ornamental shrub. The gardener recommended leaving 40 cm between individual seedlings and 10 cm from the perimeter ed - Probability - coloured balls
We have ten white, ten red, and ten blue balls in our pockets. We selected five white, two red, and three blue balls. What is the probability that we will pick a white ball in the next move? - Map distance ratio
On a map with a scale of 1:500,000, the aerial distance is equal to 12 cm. The distance by rail is equal to 100 km. The road distance is 92 km. Express the air, rail, and road distance in a step-by-step ratio. - The cone
The cone has a base radius of 12 cm and a height of 20 cm. It was truncated at 6 cm from the base. We created a truncated cone - frustum. Find the radius of the base of the truncated cone. - Tourist
A tourist walked an average speed of 3.5 km/h route in 6 hours. Calculate how many hours he would have passed at an average speed of 5.5 km/h. - Castle model
The castle model has a cone-shaped roof. The cone side is 45 cm long, and the base radius is 27 cm. a) What is the roof volume? b) How much dm² of wallpaper is used to glue the roof, i.e., the cone shell? c) What is the roof's weight if it is made of wood - Volleyball Tournament Ranking
Classes 1B, 2 A, and 3 C, participated in the volleyball tournament. How many ways could they take first, second, or third place? What is the probability that 1B will end before 2 A class? - Two Trains Meeting Time Distance
A train travels from station A to station B at a speed of 90 km/h. Another train travels from station B to station A at a speed of 45 km/h. The distance between the stations is 60 km. They leave at the same time. How long will they meet and at which kilom - Barrel Water Weight Empty
The barrel of water weighed 64 kg. When We poured 28% of the water from it on the first day and a third of the rest on the second day, it weighed 38 kg. Calculate the empty barrel's weight and the water's initial weight. - Ice Cream Cone Volume Melt
The ice cream sundae glass has a cone shape. Its height without legs is 9 cm, and its radius is 5 cm. Šimon bought eight scoops of ice cream, which all melted in the sun. One scoop of ice cream has a volume of 32 cm³. How many cm³ of melted ice cream will - Diamond and diagonals
A diamond has diagonals f = 8 cm and g = 6 cm long. How long is this diamond perimeter? (Calculate it!)
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