Maths practice for 14 year olds - page 256 of 370

Number of problems found: 7397

Cross-section 5567
What diameter must the trunk of a tree have to carve a beam with a square cross-section of 20 cm on it?
Simultaneously 5564
The smaller spiral heats the water in 30 hours, and the larger in 20 hours. How long will it take to heat the water if we turn on both coils simultaneously and the smaller coil breaks down after 8 hours of heating?
Representing 5562
The chess group consists of eight boys, representing 40% of all group members. How many girls go to the chess ring?
Orange colour
For the painter to get orange, he has to mix yellow and red in a ratio of 3:4. If he used 8 liters of red, how many liters of orange did he mix?
Trapezoid 5559
The bases of the trapezoid are 12 cm and 8 cm long. The area of this trapezoid is 40 cm². What is its height?
Diagonal 5555
The pool has a diamond shape with a side 20m long. One diagonal is 32 meters. What is the second diagonal?
Measuring 5554
The block measuring 20 cm, 10 cm, and 8 cm weighs 80 grams. What is the weight of a block made of the same material, the edges of which are half the length?
Diagonals 5551
The cube has a wall area of 81 cm². Calculate the length of its edge, wall, and solid diagonals.
Gymnasium - classes
Half of the 9th-grade students want to study at secondary technical schools, a quarter at vocational schools, a sixth at gymnasiums, and 3 students do not wish to continue their studies. How many pupils are there in the class?
Quadrangular pyramid
Calculate the surface area and volume of a regular quadrangular pyramid: sides of bases (bottom, top): a1 = 18 cm, a2 = 6cm angle α = 60 ° (Angle α is the angle between the sidewall and the base plane.) S =? , V =?
Cube edges
Find the cube edge length (in centimeters) that has a surface and volume expressed by the same numeric value. Draw this cube in a ratio of 1:2.
Burdened 5537
The product, burdened with 20% taxes, was sold for 600 CZK. How much would you sell for 10% of taxes?
Centimeters 5533
Calculate the area of one cube wall and the wall diagonal of a cube if its volume equals 1728 cubic centimeters.
Kilograms 5525
Sandra weighs the same as Markéta and 3 kg less than Justýna. All three together weigh 156kg. How many kilograms does each girl have?
Theatre performances
A total of 15,744 CZK was collected as admission for three theatre performances. The revenue from the second performance was 20% higher than the revenue from the first performance and the revenue from the third performance was 10% lower than the revenue f
Substitution
Solve equations by substitution: x+y= 11 y=5x-25
Desks
A class has 20 students. The classroom consists of 20 desks, with four desks in each of 5 different rows. Amy, Bob, Chloe, and David are all friends and would like to sit in the same row. How many possible seating arrangements exist, such as Amy, Bob, Chl
Tangent
What distance are the tangent t of the circle (S, 4 cm) and the chord of this circle, which is 6 cm long and parallel to the tangent t?
Two diagonals
The diagonals of the diamond EFGH have lengths in the ratio of 1:2. What is the circumference of a rhombus if the longer diagonal is 8 cm long?
Calculate 5499
Calculate the area of the circle, which is described by a square with a side length of 7.5 cm.

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