Math practice for 13 year olds - page 76 of 428
Number of problems found: 8555
- Lathe shaft production
The performance of three lathes can be expressed by the ratio 3:5:8. The most powerful lathe produces 136 shafts per shift. How many shafts did each of the remaining lathes make per shift? - Half of money
Mr. Investor deposited half of his money in the bank at 5% interest. He invested the other half in bonds with 7% interest. How much money did he invest when his annual profit was CZK 600? - Restaurant payment comparison
Four students were paying the bill in the restaurant. Jan paid 7 rums and 20 beers, Adam 20 rums and 7 beers, Víťa 12 rums and 25 beers, and Dan 25 rums and 12 beers. Jan paid 20% less than Adam. By how much % less did Víťa pay than Dan? - Express train distance
The express train leaves place A at 19:20 and arrives in town B at 20:24. The average speed of the express train is 15 m/s. What is the distance between cities A and B? - Boat water speed
The water in the river has a speed of 4.8 km/h relative to the bank. A boat in still water has a speed of 12.6 km/h. a) What is the boat's speed relative to the shore if it is sailing downstream and upstream of the river? b) What path will the boat travel - General trapezoid
In the general trapezoid VLAK the following hold: |VL| = 5.5 cm; |VK| = 3.5 cm; |LK| = 4.8 cm; |∢VLA| = 70°. Divide it into two triangles. Name the newly created points. Write down the lengths of the line segments. Complete the construction procedure and - Triangle angle determination
In one triangle, one angle is 43°, and the second is 15° less than the third. Determine the unknown angles of the triangle. - Cannon sound speed
A cannon fired at a distance of 2720 m from the observer. The sound of the shot was heard by the observer 8 seconds after the flash. Calculate the speed of sound propagation in the air if we assume that the observer saw the flash at the same time as the s - Egypt trip discount
A trip to Egypt was discounted by one-third of the price at the last minute. The discount was 5760 CZK. What was the original price of the tour? - School trip graders
Sixth, seventh, and eighth graders took part in the school trip. Sixth graders were 5 more than seventh graders, and eighth graders were 3 less than sixth graders. How many sixth graders were on the trip if there were 73 students in total? - 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
Eva paid €8.4 for three wreaths and five creams. Jana paid €15.6 for 9 wreaths and 7 creams. How many crowns will Jan pay for one wreath and one cream?
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