Maths practice for 14 year olds - page 21 of 195

Number of problems found: 3891

Jacket double discount
The jacket initially cost 80 euros. Then it was discounted twice, always to 80% of the previous price. How much does it cost after the second discount?
Chocolate
Chocolate, which initially cost 1.5 euros, was increased by 40%. How many euros did it cost?
Sides of right angled triangle
One leg is 1 m shorter than the hypotenuse, and the second leg is 2 m shorter than the hypotenuse. Find the lengths of all sides of the right-angled triangle.
Before yesterday
The merchant adds a sale sign in his shop window to the pair of shoes shown in the morning: "Today by p% cheaper than yesterday. " After a while, however, he decided that the sign saying: "Today 62.5% cheaper than the day before yesterday". Determine the
Positional energy
What velocity in km/h must a body weighing 60 kg have for its kinetic energy to be the same as its positional energy at the height of 50 m?
Isosceles triangle 10
In an isosceles triangle, the equal sides are 2/3 of the length of the base. Determine the measure of the base angles.
A concrete pedestal
A concrete pedestal has the shape of a right circular cone and a height of 2.5 feet. The diameters of the upper and lower bases are 3 feet and 5 feet, respectively. Determine the pedestal's lateral surface area, total surface area, and volume.
Frustum of a cone
A reservoir contains 28.54 m³ of water when complete. The diameter of the upper base is 3.5 m, while the lower base is 2.5 m. Find the height if the reservoir is in the form of a frustum of a right circular cone.
Fraction percentage comparison
What is greater: 2/5 of 10, or 20% of 4000?
Alcohol
6l 48% alcohol, how much must we add 52% alcohol to give 50% alcohol?
Cyclist speed observation
The observer sits in a room 2 m from a 50 cm wide window. A road runs parallel at a distance of 500 m. What is the cyclist's average speed on this road when the observer sees him at 15 seconds?
Cost reduction
Fourteen pieces of goods cost just as much as 21 pieces before the discount. The price of one piece after the discount is CZK 1.50 lower than before the price reduction. How much was one piece before the discount?
Cylinder and its circumference
The height of a cylinder is four times its circumference, c. What is the volume of the cylinder in terms of its circumference c?
Propeller
The aircraft propeller rotates at an angular speed of 200 rad/s. A) What is the speed at the tip of the propeller if its distance from the axis of rotation is 1.5 m? B) What path does the aircraft travel during one propeller revolution at a speed of 540 k
Reducing balance method
A company buys an item having a useful life of 10 years for 1,000,000. If the company depreciates the item by the reducing balance method, a. find the depreciation for the first year. b. Estimate the depreciation for the second and third years. c. What is
Bus catching calculation
Mr. Pozdechodim missed the bus at 10.05. At 10.10, he passed Jindra. The bus travels at an average speed of 60 km/h and Jindra at 80 km/h. Will they catch the bus, which is 20 km from the next stop?
Car meeting calculation
At midnight, a 40km/h truck will leave České Budějovice for Turnov. At 1.5 hours after midnight, a 70 km/h car drove against him. The distance between České Budějovice and Trutnov is 223 km. At what time and how far from Trutnov will the two cars meet?
Surface of the cylinder
Calculate the surface of the cylinder for which the shell area is Spl = 20 cm² and the height v = 3.5 cm.
Cuboid face diagonals
The lengths of the cuboid edges are in the ratio 1:2:3. Will the lengths of its diagonals be in the same ratio? The cuboid has dimensions of 5 cm, 10 cm, and 15 cm. Calculate the size of the wall diagonals of this cuboid.
Boys and girls
There are 20 boys and ten girls in the class. How many different dance pairs can we make of them?

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