Maths practice for 12-year-olds - page 329 of 354
Number of problems found: 7075
- Painting
Joseph and Fero painted the bench for four hours. If four friends helped him, how many hours would it take him to work? - Mukls
The six workers' working group would order jobs completed within 21 working days. How many workers must be added to complete a contract in 14 working days? - The horses
A couple of horses consume 88 kg of oats for 14 days. How many oats were consumed by seven horses at the same consumption for six days? - Wood
Peter chops wood. If they cut down a half hour a day, he would finish work in nine days. But Peter needs to finish work three days earlier. How many minutes should they cut down a day? - Cooks
Four cooks cleaned 5 kg of potatoes for 10 minutes. How many cooks would have to work cleaning 9 kg of potatoes for 12 minutes? - Greenhouses
Two workers would complete the installation of greenhouses for 54 hours. For how many hours does the installation have nine workers? - Painting school
Redecoration school had scheduled for four crew to 10 days. After two days, a single worker was ill. For how many days was the school painted when remain workers working with the same tempo? - Five tractors
Five tractors plow the field in 4.8 hours. How long would it take to plow this field if, after 1.5 hours of work, two tractors went to a different field? - Common cylinder
I've quite a common example of a rotary cylinder. Known: S1 = 1 m2, r = 0.1 m Calculate : v =? V =? Can you verify the results? - Wood
Wood contains 12% water. One m³ of wood weighs 650 kg. How many liters of water does it contain? - Cargo
The weight of the cargo car is 761 kg. The car's weight is 23% of the total weight of the car+cargo. What is the weight of the cargo load? - Pumps
The first pump flows 16 liters per second into the basin by the second pump 75% of the first and by the third pump half more than the second. How long will it take to fill the basin with all three pumps simultaneously, a volume of 15 m³ (cubic meters)? - Family
Martin has just as brothers and sisters. But his sister Jana has two times more brothers than sisters. a) How many children are in this family? b) How many boys and how many girls are in the family? - Square and circle
Into the square is an inscribed circle with a diameter of 10 cm. What is the difference between a circumference square and a circle? - Minute-hand
How long will a large (minute) hand travel on the clock for 48 minutes if its length is 56 cm? - Again saw
We have a sculpture beam from the tree trunk with a rectangular cross-section with dimensions 91 mm and 87 mm. What is the trunk's smallest diameter? - Velocipede
The front wheel of the velocipede from the year 1880 had a diameter of 1.8 m. Suppose the front wheel is turned again once, then the rear wheel six times. What was the diameter of the rear wheel? - Plumber
The plumber had to cut the metal strip with dimensions of 380 cm and 60 cm to the largest squares to no waste. Calculate the length of the sides of a square. How many squares cut it? - Gardens
The garden has a square shape with a circumference of 124 m. Divide it into two rectangular gardens; one should have a circumference of 10 meters more than the second. What size will the gardens be? - Weight of air
What is the weight of air in the living room measuring width 6 m, length 4 m, and height 2.56 m? Air density is ρ = 1.2959 kg/m³.
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