Math practice for 13 year olds - page 206 of 424
Number of problems found: 8467
- Average height
There are twice as many girls in the class as there are boys. The average height of girls is 177 cm, and boys 186 cm. What is the average height of students in this class? - Cutting the prism
A prism with a square base with an area of 1 cm² and a height of 3 cm was cut from a cube with an edge length of 3 cm. What is the body's surface formed from the cube after cutting the prism? - Half of halves
We cut half of the square off, then half of the rest, etc. Five cuts we made in this way. What part of the area of the original square is the area of the cut part? - Production 23461
The cost of production of a particular product decreased first by 15% and then by 10% of the new amount. After this reduction, it cost CZK 153. What were the original production costs? - Tourist route
How long is the tourist route when tourists cross four-sevenths of the way on foot, cross the bus twice less than on foot, and pass the last 14 kilometers by boat? - Calculate 23411
The prism with a diamond base has one base diagonal of 20 cm and a base edge of 26 cm. The edge of the base is 2:3 to the height of the prism. Calculate the volume of the prism. - Unknown 23401
27% of the unknown number is 12 fewer than 33% of the same number. Find an unknown number. - Gold, silver, bronze
How many ways can we divide gold, silver, and bronze medals if six people compete? - Interior angles
Calculate the interior angles of a triangle that are in the ratio 2:3:4. - Tournament 23371
The goalkeeper caught 188 shots during the tournament and achieved a success rate of 94%. How many shots per goal ended up in the net? - The cube
The cube and cylinder weigh the same as three 20-gram weights. Three cubes and one cylinder weigh the same as two cylinders and one cube. How many grams does one cube weigh (and one cylinder)? - IPhone eshop
An e-shop employee has lost some sales records and cannot now calculate the ratio by which the number of iPhones sold increased compared to last year. Help him calculate the ratio, knowing that the ratio of the number of iPhones sold and the ratio of the - Cone-shaped 23331
For his birthday, Jirka made a cone-shaped hat out of paper. The side of this cone is 35cm long, and the radius of its base is 20cm. How much dm of paper did Jirka use to make it? Thank you - Cone base
Calculate the circumference of the cone base; round the result to millimeters. If you know: radius 24 mm and height 46 mm. - Box and cubes
We have a box with dimensions of 20cm, 16cm, and 8cm. How many cubes can fit in it if the cube has a size of 4cm? - The angles
The angles in the triangle are in the ratio 12:15:9. Find the angles. - The farmer
The farmer calculated that the supply of fodder for his 20 cows was enough for 60 days. He decided to sell two cows and a third of the feed. How long will feed the rest of the peasant's herd last? - Calculated 23231
There are 80 screws in the box with a total weight of 1.24 kg. The weight of one screw weighs 400g. Screw weight calculated in grams - Defective 23221
The factory sets a standard that 2% of products may be defective. Last week, out of 1,250 products, 32 were defective. How many defective products were the standard exceeded? - Together 23211
Lenka is three times younger than her brother Lukas; they are 20 years old. How old is Lenka, and how many are Lukas?
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