Math practice for 13 year olds - page 63 of 429

Number of problems found: 8569

Swing balance distance
Roman and Mathias made a swing in the park by taking a 5 m-long pole and supporting it in the middle. Roman, weighing 52 kg, sat down at the left end. Where should Mathias sit to achieve balance if he weighs 60 kg? Enter the distance measured in meters fr
Apple pear price
Mrs. Havelková bought 7 kg of apples and 4 kg of pears for CZK 295. According to the receipt, she found out that 6 kg of apples and 5 kg of pears could be bought at the same cost. Determine the price of 1 kg of purchased apples and 1 kg of purchased pears
Forest Žilina hectares
There are 2.17 million hectares of forest in Slovakia. The Žilina region occupies 20% of the total area. How many hectares of forest are there in the Žilina Region?
Force moment calculation
Calculate the moment of force if F = 500 N and the arm's length is 0.8m. Unit N.m
Crane counterweight weight
What is the weight of the counterweight of a crane that lifts a 20 t weight? The arm's length is 15 m, and the arm's length with the counterweight is 10 m. Write the answer in tons.
Knife meat pressure
Grandma wanted to fry steaks for lunch. So she went to buy a large piece of meat. Calculate the knife's contact area with the meat if the grandmother cut with a force of 220 N and exerted a pressure of 1.83 MPa.
Network survey percentage
The students surveyed the number of networks on the Internet. 94% used Facebook, 19% used Twitter, and 42% used Google. How many did not use Facebook if the number of respondents was 310?
What quantity
What quantity of concrete should be ordered for concreting a rectangular family house with dimensions of 15 m × 12.6 m using permanent formwork? The depth of the foundation formed by permanent formwork is set at 80 cm. The concrete used constitutes 80% of
Number percentage difference
By what percentage is the number 15 different from the number 12?
Ladder wall height
A 3.4 m long ladder is leaning against a wall. Its lower end is 1.6 m away from the wall. At what height does the ladder touch the wall?
Rhombus diagonal perimeter
How do I find the diagonals of a rhombus if its perimeter is 80dm and one diagonal is 2x larger than the other?
Cook dessert purchase
The cook bought 54 desserts for each of the diners and paid 14.35 Euros for them. Creams were 0.30 Euro each, and Linnaeus cakes were 0.25 Euro each. How many creams and how many Linnaeus cakes did she buy?
Block edge change
The block has 10 cm, 20 cm, and 50 cm dimensions. We reduce the first edge of the cuboid by 20% and increase the second by 20%. How does the volume of the cuboid change? By how many percent?
Iron ball
Calculate the radius of an iron ball with a density of 7.8g/cm³ and a mass of 7kg.
Cashier coin payment
To pay out the amount of CZK 570, the cashier used 15 coins: a few fifty crowns and a few twenty crowns. How did she pay the amount?
Open simultaneously
An empty tank is filled with inflow in 30 minutes. A full tank is emptied in 75 minutes with an open drain. How long does it take for an empty tank to fill up if both the inlet and outlet are open simultaneously?
Elevation angle
An airliner currently flying over a location 2,400 m away from the observer's location is seen at an elevation angle of 26° 20'. At what height does the plane fly?
Worker job hours
Five workers do a job in 20 hours. How long will it take two workers to do the same job?
Battery charging capacity
The battery capacity is 50 Ah. With a current of 5A, we charge the accumulator to 100% capacity in 10 hours. To what percentage of capacity can we charge the accumulator with a current of 2A in 15 hours?
Justify
50 bottles of red wine are purchased for a company party. In the first store, a bottle of wine costs €6.90. Here they have a promotion that when you buy 4 bottles, the fifth one is free. In the second store, the same bottle of wine costs €8.50. However, t

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