Math practice for 13 year olds - page 68 of 422

Number of problems found: 8426

Rectangle and squares
A 9cm × 15cm 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 82079
The voltage at the terminals of the appliance is 4.5 V. A current of 0.5A passes through the appliance. What voltage must the appliance have if a current of 0.7A is to pass through it?
Calculate 82078
The volume of a cube is 0.512 m³. Calculate its surface area.
Throughout 82075
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
Calculate 82073
Calculate a cone's volume and surface area with base diameter d = 22 cm and body height v = 40 cm.
Borrowed 82069
You borrowed €2000 for 3 months. What amount must you pay back if the lender charges a 15% interest rate per annum?
Discount 82044
The purchase of a sweater after a 28% discount was CZK 360. How much was the shirt before the discount?
Through 82036
5 m³ of water flows through the pipe in 1 second at a maximum speed of 2 m/s. What is the pipe radius?
Suspicion 82035
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
Eva sews a costume in 6 hours, Ivana in 8 hours, and Monika in 4 hours. How long will it take them to make the costume if they work together?
Repetition: 82003
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:
Nationalities 81998
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?
Volunteers 81981
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?
Together 81979
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?
Together 81974
Two gears mesh together. The larger wheel has 56 teeth, and the smaller wheel has 20 teeth. How many times does the smaller wheel turn if the larger wheel turns 15 times?
Divided 81973
A log 88 cm long is divided into 3 parts in the ratio 3: 2: 5. How big is each part?
Passenger train
At 9:15 AM, a passenger train passes the station at a speed of 75 km/h. At 10 o'clock, an express train passes through the same station in the same direction at a speed of 120 km/h. Both trains arrive at the same destination station at the same time. a) a

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