Math practice for 13 year olds - page 71 of 414

Number of problems found: 8262

Quadrilateral prism
Calculate the volume and surface area of a regular quadrilateral prism with base edge a=24 cm if the space diagonal makes an angle of 66° with the base.
Isosceles triangle angles
Determine the size of the interior angles in an isosceles triangle if you know that the angle opposite the base is 15° greater than the angles at the base.
Father son age
The father is five times older than the son. The father will be twice as old as the son in fifteen years. How old is Dad now?
Rectangle and squares
A 9 cm × 15 cm rectangle is divided into unit squares. How many paths are there from one rectangle vertex to the opposite vertex if one can only go to the right and up the sides of the squares?
Appliance voltage current
The voltage at the terminals of the appliance is 4.5 V. A current of 0.5 A passes through the appliance. What voltage must the appliance have if a current of 0.7 A is to pass through it?
Cube volume surface
The volume of a cube is 0.512 m³. Calculate its surface area.
Metro train increase
In the metro, trains run in one direction at the same speed and the same intervals. Yesterday, there were 24 trains throughout the day. More trains will run today, as the time interval between trains will be shorter by 20%. How many more trains will there
Cone volume surface
Calculate a cone's volume and surface area with base diameter d = 22 cm and body height v = 40 cm.
Loan interest payment
You borrowed €2000 for 3 months. What amount must you pay back if the lender charges a 15% interest rate per annum?
Sweater discount price
The purchase of a sweater after a 28% discount was CZK 360. How much was the shirt before the discount?
Pipe water radius
5 m³ of water flows through the pipe in 1 second at a maximum speed of 2 m/s. What is the pipe radius?
Hotel theft suspicion
At the time of the theft, there were 96 people in the hotel; 61 were beyond suspicion. Of the 47 employees at the hotel, 23 are beyond suspicion. How many guests are not beyond suspicion?
Together sewing
Eve sews a costume in 6 hours, Ivana in 8 hours, and Monica in 4 hours. How long will it take them to make the costume if they work together?
Monogram letter combinations
Calculate how many different monograms (short name and surname) I can make from the letters A, E, M, Z, and K. a) with repetition: b) without repetition:
Resort nationality distribution
In the popular Italian resort of Caorle, there are only 4 nationalities. The resort has 3/20 Germans, 2/5 Czechs, 1/4 Austrians, and 500 Brits. How many tourists are there in total at the resort?
Afforestation workers
During afforestation, two workers planted 80 seedlings in 2 hours. At the same output, how many seedlings did 6 workers plant in 5 hours?
Position of digits
Find a number with six digits. If you put the last digit before the first, you get a new number that is five times larger. The digits between must not change their position.
Diameter of barrel
A garden barrel that is 1 m high has a base with a diameter of 80 cm. How many liters of water can fit in the barrel?
Sapling species percentage
Volunteers planted saplings in the forest nursery; spruces made up 55% of all saplings; one-third were edible, and the rest were young pines. How many saplings did they plant if the number of saplings was greater than 1060 and less than 1090?
Reward ratio division
Three friends split the reward in the ratio of 3:5:7. One of them received exactly €49. How many euros did they get together?

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