Math practice for 13 year olds - page 50 of 434
Number of problems found: 8670
- Hollow block
A hollow block is a prism with dimensions a = b = 29 cm, v = 15 cm. The wall thickness is 4.5 cm. What percent of the volume of the block in masonry is its cavity? - Skiing trip
Ski equipment costs 4560 Czech crowns (CZK or CZK) in the summer, but at the beginning of the ski season, it increases to 10032 CZK. By what percent are they more expensive? - Vertical movement
Find the length of the vertical path you must travel to lift a weight with a force of 0.01 N to do 1 J of work. - Decadal - flower bed
The castle park includes a flower bed in the shape of a regular decagon with an area of 432.8 m². Determine the distance between the adjacent vertices of the flower bed. - Clothing
Winter clothing was first sold with a 20% discount in the spring, and then the new price was reduced by another 25%. What was the original price of a winter jacket if it was sold after a double discount for 1,050 CZK? - Paving 2
It will take a construction company 8 working days to pave the sidewalks on two streets in a city if all 6 pavers work. However, only 4 pavers can complete the job because the other two have been dismissed. How many working days will it take the group of - Shadow - an observation tower
How tall is the observation tower if it casts a shadow 9.6 m long at exactly the same moment that a half-meter pole casts a shadow 30 cm long?
- Didactic test B0
A tourist cycled 28 km on an asphalt road and 25 km on a dirt road, which took 3 hours 36 min. At what speeds did the tourist travel the individual sections of the road if he rode 1.4 times faster on the asphalt road than on the dirt road? - Capacity of iron
What was the initial temperature of an iron object weighing 30 kg that, when heated to 39 degrees Celsius, absorbed 3.5 kJ of heat? The specific heat capacity of iron is 450 J/kg/°C. - Calorimetric equation
A 200g aluminum cylinder at 180°C was dropped into 3kg water at 25°C. At what temperature did the resulting temperature stabilize? The specific capacity of water is 4200 J/kg °C, aluminum 896 J/kg °C, - Box
A paper box is in the shape of a cube. 2,400 cm² of paper was used to make it. Bends for gluing the walls are not included. Calculate the volume of the box. - Frames
A framer is to prepare 23 picture frames. The frame will have dimensions of 30 cm and 42 cm. The strips from which he will make the frames are 3 meters long. a) How many frames will he make from one strip? b) How many strips will he need? - Multiple 83863
The least common multiple of 2190 and b is 13140. What is b? - Two-kilogram bread
Farmers harvested 3000 kg of rye from one hectare, from which they obtained 2500 kg of flour. 3 kg of flour will make 4 kg of bread. Calculate how many m² of land were used to grow rye, which is needed for 1 two-kilogram loaf of bread. - Emptying a tank
A water tank is emptied by one pump in 12 hours, by the second in 9 hours, and by the third in 4 hours. How many hours will it take to empty if all 3 pumps are turned on?
- Withholding 83850
An employee receives a net salary of 5000 after a 15% withholding tax. What was the gross salary? - Prepare
From two types of tea priced at 1500,-Sk and 2100,- Sk per kg, 29 kg of a mixture is to be prepared for 1650 per 1 kg. How many kilograms of each type of tea should be mixed? - Chord 24
A chord with length t = r times the square root of two divides a circle with radius r into two circular segments. What is the ratio of the areas of these segments? - Insulating a house
Five workers are working on insulating a house at such a pace that they could finish the job in 18 days. After three days of work, two workers were called away to another construction site. In how many days will the remaining workers finish the job? - It consumes
A textile machine uses 7/8 meters of fabric to sew shorts. He uses 3/5 meters more fabric to sew a T-shirt. Find out whether 30 meters of fabric will be enough to sew a set of 12 jerseys if one jersey consists of one T-shirt and one pair of shorts.
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