Math practice for 13 year olds - page 205 of 422
Number of problems found: 8427
- Cone from cube
From a wooden block 20 cm high was the turned largest possible cone. Calculate its weight if you know that the density of wood was 850 kg/m³ - Length 21863
The steel wire (α = 11.5. 10-6 1/K) has a length of 100 m at -15 °C. Find its length at 45 °C. - Cannonballs
Three cannonballs with a diameter of 16 cm landed in the castle courtyard during the battle. The castle blacksmith made balls with a diameter of 10 cm, which fit into the cannons placed on the walls. How many cannonballs did the blacksmith cast? - Diameter = height
The cylinder's surface, the height of which is equal to the diameter of the base, is 4239 cm square. Calculate the cylinder volume. - Bricklayers
The first bricklayer would build a wall in 3 days, the second in 4 days. The first bricklayer worked alone for a day, then the second bricklayer came to his aid and finished the work together. How long did it take to build the wall? - The Earth
The Earth's surface is 510,000,000 km². Calculates the radius, equator length, and volume of the Earth, assuming the Earth has the shape of a sphere. - Plums
By drying 3 kg of fresh plums, we obtained 750 g of dried plums. How many kilograms of fresh plums need to be dried if we want 1.5 kg of dried plums? - Individual 21713
They bought 22 sets of crayons for the school group. Larger sets cost CZK 65, and smaller ones cost only CZK 50. They paid CZK 1,280 for all sets. How many individual types of crayon sets did they buy? - Championships 21683
Before the World Water Polo Championships, it was necessary to fill the pool. The first pump would fill in 12 hours, the second in 15 hours, and if all three pumps were started simultaneously, they would fill the pool in 4 hours. How long would the pool b - Součková 21673
Ms. Součková bought 6 orange and 5 apple juices and paid a total of 254 CZK. Mrs. Derner bought 6 apple juice and 5 orange juice and paid CZK 2 less for them than Mrs. Součková. How much did each juice cost? - Wall and body diagonals
The block/cuboid has dimensions a = 4cm, b = 3cm, and c = 12cm. Calculate the length of the wall and body diagonals. - Emilio
Emilio made 69 potholders. Each potholder cost him $2.81 to make. How much profit will he make if he sells each potholder for $3.12? - Seedlings 21583
Mrs. Beránková bought flowers for spring planting. Begonias were CZK 35 each, and geraniums CZK 48 each. She paid CZK 1,070 for 25 seedlings. How many begonia seedlings and how many nutmeg seedlings did she purchase? - Cardholders 21563
Two cardholders will build a tower of cards in 0.5 hours. In how many hours will five such a tower be built? - Above-average 21533
The company has 1,440 employees (men and women). 18.75% of all men and 22.5% of all women received bonuses for above-average results. A total of 20% of employees were rewarded with bonuses. How many men and how many women are employed in the company? - Sixty-three 21513
Sixty-three children went to the camp. There are seven more boys than girls. How many boys went to the camp, and how many girls? - Sheets into container
How many sheets need to be closed on the block-shaped container above), which is 4 m wide, 250 cm long, and 35 dm high? How many liters of water can fit in it? - Similarity of two triangles
The KLM triangle has a side length of k = 6.3cm, l = 8.1cm, m = 11.1cm. The triangle XYZ has a side length of x = 8.4cm, y = 10.8cm, z = 14.8cm. Are triangle KLM and XYZ similar? (write 0. If not, if yes, find and write the coefficient of a similarity) - Representing 21473
Six 7th graders, representing 24% of all graders, had honors. How many students are in the class? - Circumference 21463
The circumference of the rectangle is 40cm. Find the rectangle size if you know the sides are in a 4:1 ratio.
Do you have unsolved math question and you need help? Ask a question, and we will try to solve it. We solve math question.
