Maths practice for 14 year olds - page 167 of 362
Number of problems found: 7228
- Hospital death probability
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 3000 m? - 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. - Gutter pipe material
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? - 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 40 kΩ, connected to the mains voltage (230 V)? - Resistor voltage
The current of 25 mA passes through the resistor with a resistance of 50 Ω. How much voltage do we measure on it? - Appliance resistance power
Calculate the resistance and power of the appliance through which a current of 20 mA flows at the mains voltage (230 V). - Resistor voltage How much voltage do we measure on a 400 Ω resistor when an electric current of 55 mA passes through it?
- 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. - Cube cylinder volume
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? - Apple slice ingredients
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 can plough a field in 6 hours. After 2 hours of working together, one tractor broke down. How long in total will it take to finish ploughing the field? - Ball screen
The diameter of the ball screen is 30 cm. If we add 5% of the material to be sewn, how many m² of fabric do we need to make? - Research in school
For particular research in high school, four pupils are selected from a class of 30 pupils. Calculate the number of all possible results of the selection and further calculate the number of all possible results if it depends on the order in which the stud - Four-digit numbers
Find four-digit numbers where all the digits are different. For numbers, the sum of the third and fourth digits is twice the sum of the first two digits, and the sum of the first and fourth digits is equal to the sum of the second and third digits. The di - The circumference
The circumference and width of the rectangle are in a ratio of 5:1. Its area is 216 cm². What is its length? - Two parallel chords
In a circle 70 cm in diameter, two parallel chords are drawn so that the circle's center lies between the chords. Calculate the distance of these chords if one is 42 cm long and the second is 56 cm long. - Student instrument percentage
Of the 30 students in the class, two-fifths are boys. A quarter of them are learning to play a musical instrument. 6 girls also play it. What percentage of students in this class do not play any musical instrument? - Started
A pedestrian leaves point A at a speed of v₁ = 5 km/h. After 3 hours, a cyclist sets off from the same place at a speed of v₂ = 20 km/h. At the same time as the cyclist, a car starts from point B, which is 50 km away. Calculate the distance and time at wh
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