Math practice for 13 year olds - page 258 of 428
Number of problems found: 8557
- Cube
The sum of all cube edges is 30cm. Find the surface area of the cube. - Helmet
Nowadays, better results can be obtained in cycling due to the rider's physical preparation and updated technologies. One of the essential parts of the rider's equipment is their helmet. While most bikers wear a helmet mainly to protect themselves, racers - Television quality probability
In the department store, they have 100 televisions, of which 85 are of first quality, and 15 are of second quality. The first ten buyers received a premium TV. What is the probability that the eleventh is sold a second-rate TV? - Dual increases
The two numbers are in the ratio of 5:6. If the first one decreases by ten, and the second one increases by ten, then these two numbers are in the ratio of 4:7. What are the numbers? - Chocolate Boxes Weight
They delivered 75 kg of chocolates to 214 candy boxes at the Orion plant. Some weighed 500g, others 250g. How many boxers were there? - Profit from Diluting Juice
In the restaurant, they sell 0.2 l of juice for CZK 14. The waiter rips off the guests by diluting the juice with water at a ratio of 4:1. Water costs CZK 6 for 1 liter. How much did the waiter rob guests of when he sold 10 liters of this mixture? - Rectangle JANO
The rectangle has side lengths | JA | = 16cm and | AN | = 12cm. Point S is the center of the JO side, and point T is the center of the JA side. Calculate the perimeter of the pentagon in cm. - Chocolate
I have a box of chocolate - white, milk, and dark. The ratio of white to milk with dark is 3:4. The ratio of white and milk to dark is 17:4. Calculate the ratio between white, milk, and dark chocolate. - Ages 2
A man's age is four times his son's age. After five years, he will be just twice his son's age. Find their ages. - Isosceles trapezoid
The old father decided to change the top plate of an isosceles-like trapezoid, which has basic dimensions of 120 cm and 60 cm, and a shoulder that is 50 centimeters long. How much does it pay for a new plate and a square meter worth 17 euros? - Area of a circle
The circumference of the circle is 150.72 centimeters. Calculate the area of the circle. - Two Digit Numbers Digits
How many two-digit numbers can be written using the number 0,2,6? We can also repeat the digits in the number. - Unknown Number Increase Percent
If you increase the unknown number by 14 percent, you get the number 136.8. Find an unknown number. - Hectoliters
How deep is the pool if there are 2025 hectoliters of water, the bottom dimensions are a = 15 meters b = 7.5 meters, and the water level is up to 9/10 (nine-tenths) of the height? - Three pumps
We are filling the pool. The pool would fill the first pump in 12 hours and the second in 15 hours. If all three pumps ran simultaneously, they would fill the pool for 4 hours. How long would the pool fill only with the third pump? - Four poplars
Four poplars are growing along the way. The distances between them are 35 m, 14 m, and 91 m. At least how many poplars need to be dropped to create the same spacing between the trees? How many meters will it be? - Two cities
The distance between cities A and B is 132 km. At 9.00 AM, the cyclist started the bike at an average speed of 24 km/h, and at 10.00 AM, the B cyclist at an average speed of 30 km/h. How long and far from A will they both meet? - Bricks pyramid
How many 50cm x 32cm x 30cm bricks are needed to build a 272m x 272m x 278m pyramid? - School acceptance calculation
P girls and four times as many boys applied to a certain school. After the entrance exams, a quarter of the girls and half of the boys got into secondary school. How many students were accepted into the 1st year of this high school? - Lottery Winnings
The parents won 12,000 euros. They decided to spend 34% of their winnings on Christmas presents and put the rest in the bank. How many euros did they deposit in the bank? What was the annual interest rate at the bank if they were credited with 118.8 euros
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