Math practice for 13 year olds - page 81 of 415
Number of problems found: 8285
- Gradient of the railway
Calculate the gradient of the railway line, which has an elevation of 22.5 meters in a section of 1.5 kilometers. For railways, the result is given in h (per mille). - Pyramid volume ratio
A regular quadrilateral pyramid with base edge length a = 15 cm and height v = 21 cm is given. We draw two planes parallel to the base, dividing the height of the pyramid into three equal parts. Calculate the ratio of the volumes of the 3 bodies created. - Barrel filling time
The water barrel filled to 2/3 of its volume in 42 minutes. How long will it take to fill the barrel? - Perpendicular parking
Which parking lot for 5 cars occupies a larger area, perpendicular or inclined at an angle of 45°, and how much? The car has dimensions of 4 m and 2 m. - Lottery ticket probability
In the lottery, where 326 numbers are drawn, Maros marked 7 numbers on the ticket. Kevin marked 11 numbers in another lottery, and 421 numbers were drawn. Which of these friends has a better chance of winning? - Beetle cabbage pursuit
Theodore the beetle set off from the house towards the cabbage leaf at a 20 m/min speed. Two minutes later, Max the beetle followed him at 24 m/min speed. They both came to the cabbage leaf at the same time. How far was the cabbage leaf from their house? - Park path triangle
The paths in the park form a right-angled triangle, which on the map with a scale of 1:200 has two dimensions of side lengths of 9 cm and 15 cm. Grandma walks this route every day for a health walk. How many meters does she walk? - Price discount percentage
The price before the discount is 1800. The price after the discount is 1500. What is the discount percentage? - Revolutions of cylinder
The rotating cone has a volume of 120 dm³. How tall is a cylinder of revolution with the same volume as a cone of revolution? - Beer barrel percentage
In the morning, the waiter has 200 glasses with a volume of 0.3 liters and 100 large glasses with a volume of 0.5 liters each. He starts tapping into those glasses from the 100-liter barrel. In the evening, he will have half of the small beers and a fifth - Dance course participants
Two hundred fifty-two participants signed up for the classical ballroom dance course. There were 2 times more girls than boys. How many girls and how many boys applied? - Several resistors
We have a box with the same resistors, so all of them have a resistance value of 200 ohms. Draw the connection of several resistors so that the resulting resistance is: a) 100 b) 120 (only 4 resistors) - Liquid volume reduction
The warm liquid in the container reduced its volume by 2/27 after cooling By what percent was the warm liquid's volume greater than the cooled liquid's? - City distance centimeters
The cities are 400 km apart; how many cm is it on a 1:400,000 scale map? - Basket candy ratio
There are lollipops, chocolates, and candies in the basket. The number of lollipops and chocolates is in the ratio of 2:3, and the number of chocolates and candies is in the ratio of 4:5. There are 15 fewer candies than lollipops and chocolates combined. - Examples on solutions
Example no. 1: For the preparation of a 2% solution we need 20 l of water. How many ml of preparation do we use? Example no. 2: How many litres of water/preparation do we need for the preparation of 20 litres of a 2% solution? Example no. 3: How many litr - Dana book pages
Dana read the book in 4 days. On the first day, she read a third of the book; on the second day, a sixth of the book; on the third day, half of the remaining pages. She still had 30 pages left on the last day. How many pages was the whole book, and how ma - In 20
In 20 years, the father will be twice as old as he was five years ago. How old is a dad now? - Stadium spectator percentage
There are 13,000 spectators in the stadium. Five thousand eight hundred fifty sat. What percentage was seated? - Milan Eduard savings
Milo saved 120 euros per year, and Eduard saved 150 euros. By what percentage did Eduard save more?
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