Math practice for 13 year olds - page 376 of 422
Number of problems found: 8427
- Two boxes-cubes
Two boxes of a cube with edges a=28 cm and b = 92 cm are to be replaced by one cube-shaped box (same overall volume). How long will its edge be? - Equilateral cylinder
The equilateral cylinder (height = base diameter; h = 2r) has a V = 178 cm³ volume. Calculate the surface area of the cylinder. - Masons
One mason casts 30.8 meters square in 8 hours. How long casts four masons 178 meters square? - Chord AB
What is the chord AB's length if its distance from the center S of the circle k(S, 50 cm) is 43 cm? - Silver medal
A circular silver medal with a diameter of 10 cm is an inscribed gold cross consisting of five equal squares. What is the area of the silver part? b) What is the area of the Golden Cross? - Rectangle and circle
The rectangle ABCD has side lengths a = 40 mm and b = 30 mm and is circumscribed by a circle k. Calculate approximately how many centimeters a circle is long. - The star
Find the area of the shaded part of the square with a side of 22 cm. - Clocks
What distance will describe the tip of a minute hand 6 cm long for 20 minutes when we know the starting position with finally enclosed hands at each other at 120°? - Annulus
Two concentric circles form an annulus with a width of 10 cm. The radius of the smaller circle is 20 cm. Calculate the area of the annulus. - Arc
What area of a circle occupied the flowers planted in the arc of a circle with a radius 3 m with a central angle of 45°? - Jane and Miro
Jane's brother Miro is 42 years old. He is three times as old as Jane when Miro was for as many years as there are now Jane. How old is Jane? - Circle sector
The circular sector with a central angle 160° has an area 452 cm². Calculate its radius r. - Janitor
The janitor tosses 28 cm layer of snow on the school grounds for 90 minutes. How many friends would have to call for help if snow needs to have bowled for 15 minutes? We assume that at the same time, we all have the same amount of snow. - Troops - soldiers
Food stocks will last 20 soldiers during the four-day training. If four soldiers become sick, how many days could they extend training? - Pumps 3
Two pumps of the same power fill the garden pool for 10 hours. How many of these pumps would we have to use if we want to shorten the filling of the pool to four hours? - Hurry - rush
I will travel from the school to the bus stop at an average speed of 7 km/h for 24 minutes. How fast do I need to go if I need to get there in 17 minutes? - Floating floor
In the new building, a floating floor worker is considered in each room. Thirty minutes lay 9 m² of the floor. How long did three workers lay the floor in four rooms with a total area of 90 m²? - Tea blend
Tea blends are made from two kinds of tea. In standard tea, the mixture is two teas in a ratio of 1:3, and 40 g costs 42 CZK. In the premium tea mixture, weighing two teas in the 1:1 and 50 grams ratio costs 60 CZK. How much cost 10 grams of a more expens - Class pairs
In a class of 34 students, including 14 boys and 20 girls. How many couples (heterosexual, boy-girl) can we create? By what formula? - Family parcels
The father will divide the land so that the older son has three bigger parts than the younger son. Later elder son gave a 2.5 ha field to the younger, and they had both the same. Determine the area of the family parcel.
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