Math practice for 13 year olds - page 54 of 422

Number of problems found: 8429

Equilateral shell
The glass weight has the shape of a regular four-sided pyramid with a base edge of 10 cm. The shell walls are equilateral triangles. What is the weight in grams of the paperweight if the density of the glass is 2500 kg/m³?
Percentage 83320
The company's monthly production increased from 352 products to 528 products. So, by what percentage did the original monthly production increase?
Calculate 83311
The surface of the cuboid is S = 1714 cm². The edges are 25 and 14 cm long. Calculate its volume.
Married pairs
In how many ways can we seat five guests at a table, two of whom are married and want to sit next to each other?
Quadrilateral prism
The diagonal of section DBFH of the regular quadrilateral prism ABCDEFGH inscribes a circle with a diameter of 8 cm. What is the volume of the prism?
Calculate rhombus
Calculate the height of the rhombus ABCD on side BC if AB=7cm, BC=5.5cm, and the height of the first side on AB=4.4cm.
Numbers 83301
On the number line, display all real numbers greater than or equal to two and less than 5.
Peleton
In a cycling race, the peloton travels at an average speed of 36 km/h. One competitor took 5 minutes to repair a puncture. How many kilometers per hour was his speed greater than the speed of the peloton when he caught up with him in 20 minutes? How long
Apples 83295
The price of 6 kg of pears is CZK 77 higher than the price of 5 kg of apples. The price of 6 kg of apples is the same as the price of 5 kg of pears. How much are 2 kg of apples?
Doubravka 83293
Evelyn plows the garden in four hours, while her friend Doubravka can do it in three hours. Evelína started work at 1 p.m., and an hour later, Doubravka joined her so they could go swimming together. Calculate the time the girls can go to the swimming poo
Candies 83291
Jana and Klara divided the candies in a ratio of 15:18. Klára got 90 candies. How many candies were there?
Another 83290
Petra pushed a chair from one room to another with a force of 60N. She did 300 J of work. How far did Petra push the chair?
Bicycle wheel
What is the diameter in centimeters of the wheel of a bicycle if it turns 2000 times on a track 4082 m long
Cancel variations
Evaluate the following expression with factorials: (45!-44!)/(44!)
Employees 83264
The company laid off employees during the crisis, so at the end of the crisis, it had 40% fewer employees than before the crisis. When the company hired 42 new employees after the crisis subsided, it had 25% more than at the end of the crisis. How many em
Quadrilateral 83254
What is the volume of a regular quadrilateral pyramid if its base edge a = √18 cm and side edge b = 5 cm?
Percentage 83250
There were four times more girls than boys at the show. By what percentage were there more girls than boys at the show?
Calculate 83248
The cube ABCDEFGH has an edge of length 3 cm. Calculate the volume of the pyramid ABCDH.
Isosceles 83247
Calculate the lengths of the sides in an isosceles triangle, given the height (to the base) Vc= 8.8cm and the angle at the base alpha= 38°40`.
Decoration
Jarka and Jana decided to decorate their common room. If Jarka painted it alone, it would take her 4 hours, and Jane 3 hours. How long would they paint the room if they painted together?

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