Math practice for 13 year olds - page 320 of 434
Number of problems found: 8665
- Ten-liter 4524
3 mm of water rained down on the garden with an area of 800 m². How many ten-liter cans did this rain replace?
- Rectangle 4523
How high must the box, the bottom of which is a rectangle with sides of 40 cm, 625 mm, have a volume of 1 hl?
- Trees
A young tree is 16 inches tall. One year later, it is 20 inches tall. What is the percent increase in height?
- 2d shape
Calculate the area of a shape in which an arbitrary point is not more than 3 cm from the segment AB. The length of segment AB is 5 cm.
- Rectangle 3-4-5
The sides of the rectangle are in a ratio of 3:4. The length of its diagonal is 20 cm. Calculate the area of the rectangle.
- Passenger 4513
From two cities, A, and B, 210 km apart, two cars left at the same time at 8:00 AM opposite each other. A truck left place A at a speed of 60 km/h, and a passenger car left place B at 80 km/h. At what time did the cars meet?
- Vehicle tank
A vehicle tank was 3/5 full of petrol. When 21 liters of fuel was added, it was 5/6 full. How many liters of petrol can the tank hold?
- Cross-section 4507
How much soil needs to be removed when digging a 200 meter long ditch whose cross-section is an isosceles trapezoid with an area of 4812.5 cm²?
- Regular n-gon
Which regular polygon has a radius of circumscribed circle r = 10 cm and the radius of inscribed circle p = 9.962 cm?
- Harvesters 4498
The first combine harvester will harvest the fields in 12 hours, and the second combine harvester in 8 hours. How long does it take for the same harvester to harvest the 3rd combine if all three harvesters harvest together in 2 hours?
- Average speed
When the bus stops at a bus stop, the average speed is 45 km/h. It would drive at 54 km/h if it did not stop. How many minutes of every hour does it spend at stops?
- Obtained 4484
25% oil is obtained from one flaxseed. From how many kg of flax seeds is 1.5 kg of oil obtained?
- Aircraft 4480
Two planes take off simultaneously from airports A and B, fly towards each other, and meet in 20 minutes. The distance between the airports is 220 km, and the average speed of the aircraft flying from airport A is 60 km/h more than the average speed of th
- Simultaneously 4479
A worker would fill the tank with one inlet in 36 minutes, the other in 45 minutes. How long will it take to fill the tank if the water flows through the first inlet for 9 minutes and then both simultaneously?
- Expensive 4478
Five liters of white wine and six liters of red wine cost 432 CZK. One liter of red wine is CZK 6, which is more expensive than one liter of white wine. Thus, we pay CZK 6 for one liter of white wine and CZK 6 for one liter of red wine.
- Diagonals of a rhombus
One of the diagonals of a rhombus is twice the other. If the sum of the lengths of the diagonals is 24, find the area of the rhombus.
- Father and sons
After 15 years, the father will have as many years as his two sons together now. There is a six-year difference between the brothers, and the older one celebrated fifty years three years ago. How old is their father now?
- Pharmacy
The pharmacy adds 3 liters of 95 percent alcohol and 5 liters of 38.04 percent alcohol. How much percent alcohol did the pharmacy get?
- Temperature 4474
Mom is going to wash by hand in water that should be at 40°C. The tub already has 10 liters of water at a temperature of 12.3°C and can still hold 5 liters. What temperature should the water be allowed to be?
- Equation: 4472
Solve the equation: x!: 5 = 1008 The solution to the equation is a natural number.
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