Math practice for 13 year olds - page 82 of 435
Number of problems found: 8682
- Cylinder 80733
How tall is a cylinder whose shell has a volume equal to the base? What is the volume of this cylinder?
- Quadrilateral 80729
Quadrilateral ABCD has side lengths AB=13cm, CD=3cm, AD=4cm. Angles ACB and ADC are right angles. Calculate the perimeter of quadrilateral ABCD.
- Fifty-meter 80722
Calculate how many hectoliters of water can fit in a fifty-meter sloped pool; if the smallest depth is 1.2 m and the largest depth is 3 m, the width of the pool is 20 m.
- Percentage 80721
Calculate what percentage is €37 from €49.
- Cube-shaped 80720
Pavel has a cube-shaped aquarium with a volume of 240 liters. Thomas has an aquarium whose all dimensions are half the dimensions of Paul's aquarium. What is the volume of Thomas's aquarium?
- Hibernation 80718
The bear weighed 410 kg at the beginning of winter and lost 10 percent during hibernation. He gained 10 percent of his weight from spring to fall. Find out if the bear's weight was greater at the beginning of winter or autumn by what percentage.
- Effectiveness 80711
When testing the effectiveness of an electric cooker with data of 220 V, 1200 W, 1 kg of water at a temperature of 15 degrees Celsius was boiled for 8.5 minutes. Calculate the stove efficiency corresponding to these data
- Percentage 80710
Calculate what percentage is 12€ of 60€.
- Resistances 80706
The current I = 4A branches into three wires with resistances R1 = 2Ώ, R2 = 5Ώ, R3 = 10Ώ. Calculate the total resistance of the connection and the voltage of the source. How big are the currents in each wire?
- Current in the bulb
The bulb is rated 6 V, 0.2 A. Determine the current rating of the bulb.
- Automatically 80704
The electric circuit breaker automatically switches off the circuit of the 220 V electrical network at a current of 6 A. Determine the maximum power in the protected circuit.
- Resistance 80703
An immersion cooker has a resistance of 30 ohms and is connected to a voltage of 120 V. How much heat is generated in 2 hours?
- Consumption 80702
A current of 500 mA passed through the filament of a light bulb with a resistance of 400 ohms. What is the consumption of a light bulb in 5 hours?
- Resistance 80699
The immersion cooker plate has data 220 V, 300 W. What is the resistance of the heating wire?
- Resistance 80698
The electric iron plate has written 220 V, 1200 W. What is the resistance of the heating wire?
- Crossbars 80697
Calculate the length of the middle crossbars in an isosceles triangle if the length of the arm is 52mm and the base height is 48mm
- Application 80696
A worker makes 12 furs in 12 hours. One truck has 20 m³. The price for the application is 2.45 euros/m³. What will be the hourly output in euros?
- Sweaters 80695
Out of 400 sweaters, 5% are second quality, and the rest are first quality. How many sweaters are of first and second quality?
- Follows 80693
A train travels at a speed of 50 km/h from city A. In 15 minutes, a second train follows him at 20 m/s. We are sitting on the first train. When will the second train catch up with the first?
- Single-digit 80674
There are cows, ducks, and geese on the farm. They have a total of 126 legs. Ducks are 3 more than houses. And there are 20 cows. If we count all the animals, we have to divide them by the number three, and we should get a single-digit number.
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