Maths practice for 14 year olds - page 280 of 309
Number of problems found: 6169
- 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?
- Wood
Wood contains 12% water. One m³ of wood weighs 650 kg. How many liters of water does it contain?
- Uranium ore
Uranium ore contains 0.2% pure uranium, and pure uranium includes 0.07% fissile uranium. How many grams of fissile uranium has 2800 ton of uranium ore?
- 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?
- Percentage 1544
Almost 60% of the country's area is permanent crops. 30% of permanent crops are orchards. What percentage of the area of the state is occupied by fruit orchards?
- Container
On the first day, I removed 1/4 of the water from the full container, and on the second day, I removed 1/5 of the remaining water. Thus, how many percent remain container-filled?
- Influenza
For the first week of February, by influenza, 5% of children were in kindergarten. In the second week ill, nine next children, bringing the number of patients increased to 20%. How many children went to kindergarten?
- 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)?
- Unknown number 10
The number first increased by 30%, then by 1/5. What percentage we've increased the original number?
- Potatoes 1537
Potatoes contain 65% starch. How many potatoes do we need to get 13 kg of starch?
- Crowns
1180 crowns are divided into three: A got 20% less than B, and C got 15% more than B. How many got A, B, and C?
- Repair company
The company repairs cars. On the first day, repair half of the contract; on the second day, half of the rest; and on the third day 8 residue cars. How many total cars did the company repair?
- The city
At the end of 2010, the city had 248000 residents. The population increased by 2.5% each year. What is the population at the end of 2013?
- Triangular pyramid
A perpendicular regular triangular pyramid is given: base side a = 5 cm, height v = 8 cm, volume V = 28.8 cm³. What is its area (surface area)?
- Percentage of waste
In a square plate with a side 75 cm, we cut four same circles. Calculate the percentage of waste.
- Concentric circles
In the circle with diameter, 13 cm is constructed chord 1 cm long. Calculate the radius of a concentric circle that touches this chord.
- Circle and hexagon
Calculate the radius of a circle whose circumference is 8.4 cm longer than the inscribed regular hexagon's circumference.
- 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?
- Balls
The urn is eight white and six black balls. We pull four random balls. What is the probability that among them will be two white?
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