Maths practice for 14 year olds - page 65 of 347

Number of problems found: 6935

Rectangle dimension increase
The area of the rectangle is 81.25 cm². If we increase its length by 5 mm, its area increases by 4%. Determine its dimensions.
Square side reduction
A square has a side length of 25 cm. How big is its area if the side is reduced by 25%?
Quadrilateral triangle segment
The quadrilateral ABCD is symmetrical about the diagonal AC. The length of AC is 12 cm, the length of BC is 6 cm, and the interior angle at vertex B is right. points E and F are given on the sides AB, and AD so that the triangle ECF is equilateral. Determ
Circumference of edges
The hexagon pyramid has a circumference of 120 cm, and the length of the side edge is 25 cm. Calculate its volume.
Number percentage more
The number 420 is 20% more than the unknown number. What is the unknown number?
Three-digit - sum
A three-digit number has a digit sum of 16. If we change the digits in the hundreds and tens places in this number, the number is reduced by 360. If we swap the ten's and one's digits in the original number, the number increases by 54. Find this three-dig
Banknote payment euros
Participants paid out 3,300 euros in 40 banknotes. Some were 50e, and others were 100e. How many were there?
Bus highway speed
Tourists traveled by bus to Croatia. They drove the highway in 8 hours at an average speed of 100 km/h. How fast would they cover it if they walked at an average speed of 120 km/h?
Map scale reduction
Cyril marked a square plot of land on a map with a scale of 1 ∶ 50,000 and calculated that its side corresponds to 1 km. He reduced the map on the copier so that the marked square had an area smaller by 1.44 cm² than on the original map. What was the scal
Younger Carlos
In 2005, Peter was three times as old as Carlos. In 2020, Carlos was half his age younger than Peter. In which year was Peter born and in which Carlos?
Painter fence work
Two painters are painting the factory fence together. If everyone worked alone, the first would finish the job in 16 days, the second in 20 days. When will they finish the work together?
Apricot peach purchase
We paid a total of 85 crowns for the purchase of 2.5 kg of apricots and 1.5 kg of peaches. A kilogram of peaches is CZK 2 cheaper than a kilogram of apricots. How much CZK was paid for the apricots?
Tie price calculation
CZK 895 was paid for three ties. A blue tie was 18% more expensive than a gray one, and a brown one was CZK 100 more expensive than a gray one. Calculate the prices of individual ties.
Free fall velocities
Calculate the instantaneous free fall velocities at the end of the 1st, 3rd, 5th, and 7th seconds. Compile the results in a table.
Spherical segment
Calculate the volume of the spherical segment and the surface area of the canopy if the radius of the sphere is r = 5 cm and the radius of the circular base of the segment ρ = 4 cm.
Circumscribed - sphere
A cube with a volume of 4096 cm³ is described and inscribed by a sphere. Calculate how many times the volume of the circumscribed sphere is greater than the inscribed sphere.
Pavla Irena age
Paula is 2x older than Irene. Four years ago, Paula was 6 times as old than Irene was then. In how many years will the ages of Paula and Irene be in the ratio of 4:3? Thanks
Everyone age average
There are 10 students in the drama club. We count everyone's age in whole years. The average age of the girls is 12.25 and the boys 12.5, and the average age of all is 12.3. How many girls and how many boys are there in the class?
Cyclist peloton speed
The front of the cycling peloton travels at an average speed of 48 km/h. The cyclist with the green T-shirt lost 5 minutes when he fell. What speed must he drive if he wants to reach the front of the peloton in twenty minutes? Possible?
Triangle angle operations
There are also two equilateral triangles ABC, and BDE, such that the size of the angle ABD is greater than 120° and less than 180° points C and E lie in the same half-plane defined by the line AD. The intersection of CD and AE is marked F. Determine the s

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