Maths practice for 14 year olds - page 52 of 375

Number of problems found: 7497

Trapezoid base perimeter
The isosceles trapezoid has a base length of 12 cm, a height of 4.5 cm, and a height of 5 cm. What is its circumference?
Michal computer saving
Michal is saving for a new computer. His parents gave him 130 euros, which was 26 percent of the total amount. He received 20 percent of the price of the computer from his grandmother, and his aunt added another 35 euros. How many euros does Michal still
Roofer roof days
Three roofers cover a third of the roof in 10 days. In how many days would 5 roofers cover the entire roof at the same rate?
Tree watering distance
There are 10 trees in a row with the same spacing x = =3 meters. How many meters does a person travel if he waters two trees at once
Body current voltage
A current of 0.1 A can lethally affect a human body with a resistance of 3 kΩ. What voltage corresponds to this current?
Bulb voltage current
A current of 275 mA passes through the filament of a light bulb with a resistance of 800 Ω. What voltage is the bulb connected to?
Lever force distance
Calculate at what distance from the axis of rotation a force of 60N acts on one side of a double-return lever; if a force of 180N acts on the other side at a distance of 1 meter from the axis of rotation, the lever is in equilibrium.
Karel digit error
Karel had to multiply two two-digit numbers. Out of care, he changed the order of the digits in one of the factors and got a product that was 4,248 less than the correct result. What is the correct result? How much should Karl have earned?
Current thermal energy
How long will it take for a current of 8A in a resistance of 30 ohms to develop thermal energy of 3 MJ if the efficiency of converting electrical energy into heat is 90%?
Number ratio subtraction
I think two numbers. Their ratio is 5:7. If 3 is subtracted from the first and 7 from the second, then the ratio is 6:7. What number was I thinking?
Cube triangle volume
In the cube ABCDEFGH, the area of triangle ABK is √20 cm². How much cm² is the volume of ABGH in a cube if you know that K is the midpoint of edge CG?
Triangle area side
Calculate the area of an isosceles triangle ABC with a base of 10 cm and a side of 7 cm. Sketch a picture.
Trapezoid perimeter base
An isosceles trapezoid has one base twice as short as the other. Its area is 42 cm², and its height is 4 cm. Calculate its circumference if you know that the arm is 5.3 cm long.
Prism pyramid ratio
For the volumes of a perpendicular prism and a pyramid with the same base and height: A) the volumes are equal B) the volume of a pyramid is three times smaller than the volume of a prism C) the ratio of the volumes of the prism and the pyramid is 1:3 D)
Castle tour time
The tour of the castle takes 72 minutes, and the tour of the cellar took half the time compared to the tour of the interiors. In the garden, visitors then spent 20% of the time they were inside (in the cellar and the castle). How long did the tour of the
Peter example solving
Peter solves 40 examples. For a correctly solved example, he receives CZK 5 from his mother. For example, in a poorly solved case, he will pay 20 CZK to his mother. After solving all the examples, he had CZK 25 more than when he started counting. How many
Banknote payment count
CZK 8,000 was paid out in fifty pieces of banknotes in denominations of CZK 100 and CZK 200. How many were there?
Triangle height line
In the right triangle KLM, the hypotenuse l = 9 cm and the perpendicular k = 6 cm. Calculate the size of the height vl and the line tk.
Triangle interior angles
Calculate the interior angles of the triangle. The angle alpha is 16° greater than beta, and the angle gamma is 17° less than alpha.
Glass cocktail level
The cone-shaped glass has a volume of 2.5 dl and a diameter of 13 cm. How much cocktail is left in the glass if the level only reaches half the height of the glass?

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