Math practice for 13 year olds - page 78 of 415
Number of problems found: 8285
- Cone surface volume
The cone's surface is 75.36 cm, and the radius is 3 cm. Calculate the volume of the cone. - Car average speed
A car drives for an hour on the highway at a speed of 100 km/h, then for half an hour at a speed of 80 km/h, and for another half hour in the field at a speed of 20 km/h. What track did he run together? What is the average speed of the car? - Dye water proportion
Pour 9 dl of dye into 100 liters of water. What will be the proportion of dye in the resulting mixture? Express as a percentage. - Volleyball rack capacity
Calculate how many volleyballs with a circumference of 65 cm fit into a cube-shaped rack whose edge is 100 cm long. - Fraction addition division
Add one-third to five-eighths and divide the result by the sum of the numbers five-quarters and two-thirds. - Number double reduced
It is necessary to determine the number whose double is reduced by 15 equals the number 5. - Puzzle wood density
The picture puzzle made of wooden cubes weighs 0.792 kg. One cube has an edge length of 4 cm and a weight of 33 grams. Find out how many cubes make up a puzzle and calculate the wood density in kg/m³. - Gunpowder component mixture
Gunpowder is made from a mixture of coal, sulfur, and lignite, with 4 times more lignite than sulfur and 3 times more sulfur than coal. Calculate how many kilograms of individual components are needed to produce 240 kg of gunpowder.? - Natural number sum
Calculate the sum of the squares of single-digit natural numbers less than 6 - Wreath cream price
Eve paid €8.4 for three wreaths and five creams. Jane paid €15.6 for 9 wreaths and 7 creams. How much will Jane pay for one wreath and one cream? - Three ratios
Calculate x in terms of: x:7=6:4 1/2:x=5:3/4 4:3=8:x - Pupil number decrease
Over five years, the number of pupils in the school decreased from 455 to 335. By what percentage did the number of pupils decrease? - Dress double discount
Dresses that initially cost 100 € after a double discount of 10% subsequently increased in price by 20%. How much did they cost? - Spherical layer volume
Sketch a spherical layer formed from a sphere with a radius of r= 8.5 cm, given: v=1.5 cm, r1=7.7 cm, r2=6.8 cm. What is its volume? - Class boy girl
There are 32 children in the class. If there were three more boys and one less girl, there would be an equal number of girls and boys in the class. How many boys are there in the class? - Savings ratio three
The savings of Victor and Peter are in the ratio of 15:8, and the savings of Peter and George are in the ratio of 2:1. What is the ratio of the savings of Victor, Peter, and George? - Plate glass ratio
5 out of 32 plates and 2 out of 20 glasses were broken at the party. What is the ratio of plates to glasses now? - Pavel Vojta trees
Paul and Victor were planting trees at a forestry work camp. Paul planted two more trees than Victor in each six-hour shift. Together, they planted 156 saplings in three shifts. How many saplings did each of them plant? - Diamond tile paving
How many diamond-shaped tiles with a side of 25 cm and a height of 20 cm are needed to pave a rectangular courtyard with sides of 30 m and 28 m if the joints represent 1/20 of the area? - Mr. Quick
Mr. Rychlý needs to drive from Brno to Prague. There is an oversized load on the D1 motorway, which leaves Brno at 11:00 p.m. at a speed of 12 km/h. What is the latest time Mr. Rychlý can depart to avoid getting caught behind the load, i.e. to reach the H
Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
