Maths practice for 14 year olds - page 164 of 379
Number of problems found: 7567
- Resistances 25271
Three resistors with resistances of 200 Ω, 400 Ω, and 600 Ω are connected in series (in series)—a current of 1.8 A flows through the first 200Ω resistor. a) What current passes through the second and what current through the third resistor? b) What are th
- Diamond area from diagonals
In the diamond, ABCD is AB = 4 dm, and the diagonal length is 6.4 dm long. What is the area of the diamond?
- Lowest voltage
Three resistors with resistors R1 = 10 kΩ, R2 = 20 kΩ, R3 = 30 kΩ are connected in series and an external voltage U = 30 V is connected to them. On which resistor is the lowest voltage?
- Height of pyramid
The pyramid ABCDV has edge lengths: AB = 4, AV = 7. What is its height?
- Statistically 25181
Statistically, in a city of 100,000 inhabitants, 600 people die in one year. During the year, 2,000 people received hospital treatment, and 120 of them died there. Calculate the probability that a citizen who comes to the hospital for treatment will die t
- Aircraft climbing
The average climb angle of the aircraft is 11° 20', and its average speed is 400 km/h. How long does it take to climb to a height of 3000m?
- The rectangle
The rectangle has a circumference of 32 m. One side is 2 m longer than the other side. Calculate the side lengths of this rectangle.
- Half-cylinder 25121
How much sheet metal do we use to produce a gutter pipe in the shape of a hollow half-cylinder 20 m long and 16 cm wide if we count 8% for bending and welding?
- Everything in soup
The pot with soup is shaped like a cylinder with a bottom diameter of 20 cm and a height of 24 cm. How many guests will we have enough soup for if the pot is filled to two-thirds of the height and 0.25 l of soup is calculated per person? (pay attention to
- Circle and square
An ABCD square with a side length of 100 mm is given. Calculate the circle’s radius that passes through vertices B, C, and the center of the side AD.
- Mains voltage
How much electric current flows through the appliance with a resistance of 40kΩ, connected to the mains voltage (230 V)?
- Resistance 25031
The current of 25 mA passes through the resistor with a resistance of 50Ω. How much voltage do we measure on it?
- Resistance 25021
Calculate the resistance and power of the appliance through which a current of 20mA flows at the mains voltage (230 V).
- Electric 25011
How much voltage do we measure on a 400Ω resistor when an electric current of 55 mA passes through it?
- Double ratio
The mobile phone was twice gradually discounted in the ratio of 3:2 and one-half: five-quarters. If the price was CZK 4,200 after a double discount, how much did it initially cost?
- Copper Cu wire
Copper wire with a diameter of 1 mm and a weight of 350 g is wound on a spool. Calculate its length if the copper density is p = 8.9 g/cm cubic.
- Percentage 24931
There is a cylinder with the largest possible volume in the cube with an edge of 6 m. What percentage of the volume of a cube has the volume of a cylinder?
- Kilogram 24921
Dahlia cooks with her mother's apple slices. They mixed flour, sugar, and butter in a ratio of 10:3:2. How many grams of sugar and butter did they put in half a kilogram of flour?
- The field
Three tractors plow the field in 6 hours. However, after 2 hours, one tractor broke down. How long will the field be plowed?
- A number
A number 5% greater than 75?
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