Math practice for 13 year olds - page 70 of 422
Number of problems found: 8429
- Custom-made 81913
On October 1, 2022, the customer ordered a custom-made kitchen from a carpentry company. Delivery time is 1 month. Four carpenters should work on the order in the workshop for 21 working days. Will they be able to deliver the kitchen on time if one of the
- Transferred 81895
The tin body transferred 150,000 J of heat, and its temperature dropped by 10°C. Calculate the mass of the tin body. (c of tin is 0.227 kJ/kg. °C). Enter the resulting weight in grams and round it to two decimal places.
- Temperature 81892
By how much °C will the temperature of an iron key weighing 0.004 t change if it receives 360,000 J of heat? ( c of iron is 450 J/kg.°C )
- Temperature 81891
Calculate the mass heat capacity of a steel body weighing 2 kg, which was heated from an initial temperature of 15°C to 80°C by supplying 60 kJ of heat.
- Difference 81888
The ropeway climbs at an angle of 22°30'. Calculate its length if the height difference between the lower and upper station is 560m. Sketch a picture
- Building 81885
A ladder leans against the building; its length is 7.5 meters. The bottom is 2 meters away from the building. At what height is it leaning against the wall?
- Pythagorean 81883
Hello, I have a problem calculating the height on side z in the general triangle XYZ, where z=4 cm, x=1.5 cm, and y=3.7 cm. It was assigned in 8th grade when discussing the Pythagorean theorem. Thank you.
- Cross-section 81879
The castle has a length of 4 m and a cross-section in the shape of a square whose side is 15 cm long. Eight such castles must be painted. One kilogram can is enough for 6 m² of coating. How many cans of paint should be bought?
- Makarska riviera
The motor boat departs from Baška Voda at 19:15 and arrives in Makarska at an average speed of 30 km/h at 20:00. However, a group of tourists from Germany must be in Makarska a third of the time earlier. What should the average speed of the boat be?
- Identical 81873
Three identical pumps empty the tank in 1.8 hours. How long will it take 5 pumps to empty this tank?
- Municipal 81852
Six workers repair 48 meters of municipal road in 2 days. How many days will 3 workers with the same output repair 60 meters of the road?
- Surroundings 81843
A copper cylinder weighing 15 kg transferred 114.9 kJ of heat to the surroundings during cooling. By how many degrees Celsius did it cool down?
- Probability 81842
In an opaque bag are chips with numbers from 1 to 20. What is the probability that we will draw a chip with a number less than 16?
- Bought 81839
Jane lacked 160 crowns to buy six rings, so she only bought four and had 100 crowns left. How much are 4 rings?
- Perpendicular 81837
Two neighboring cottagers have cottages under the forest by the stream. They decided to build a bridge over the stream at a place far from the two huts. The distance between the cottages is 230 m; one cottage is 120 m from the stream, and the other is 85
- Hectoliters 81834
They filled the 25m long, 15m wide swimming pool with water to a height of 80cm. How many hectoliters of water did they put in, and how long did it take for the pool to fill if 375 hectoliters flow in 1 hour?
- KiloJoules energy
In the washing machine, 6 liters of water were heated from a temperature of 22 degrees to 62 degrees. Find out the weight of 6 liters of water. What heat (in kJ= kiloJoules) did the water receive?
- Department 81809
Three times more boys than girls go to the Jude section. If three more girls started dating, there would be twice as many boys as girls. A) determine how many go to the girls' section B) determine how many children attend the department in total.
- The soap
The soap has the shape of a cuboid with dimensions of 6 cm, 4 cm, and 2 cm. Katy used it for a week and all the dimensions of the soap shrunk by half. How long will her soap last?
- Calculated 81804
Mr. Hovorka pays a monthly flat rate of CZK 100 plus CZK 0.90 for each started minute of the call for his mobile phone. He calculated that each minute of the call last month cost him CZK 2.15. How many minutes was he on the phone?
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