Maths practice for 12-year-olds - page 265 of 359
Number of problems found: 7167
- Four circles
1) Calculate the circle radius if its area is 400 cm² 2) Calculate the radius of the circle whose circumference is 400 cm. 3) Calculate circle circumference if its area is 400 cm² 4) Calculate the circle's area if the perimeter is 400 cm. - Lawn mowing
A father and son mow the lawn in 3 hours. How much would a father do on his own if they both cut just as fast? - Calculate
Calculate the area of a circle whose radius is 5 dm. - Workers digging
The three workers will dig one big pit in two days. How many workers would dig seven large pits in three days? - Annulus
The radius of the larger circle is 8 cm, and the radius of the smaller is 5 cm. Calculate the area of the annulus. - Alarm clock
The old watchmaker has a unique digital alarm in its collection that rings whenever the sum of the alarm's digits equals 21. Find out when the alarm clock will ring. What is their number? List all options. - The surface
The cuboid's surface area is 1714 cm2, and the edges of the base are 25 cm and 14 cm long. Find the area of the surface. - Every day 7 pages
Anelka reads the book seven pages every day. When she reads one more page a day, she will read it three days earlier. How long will Adelka read a book? How much does a book of pages have? - Square prism
Calculate the volume of a square prism with a height of 2 dm and a base that is a rectangle with sides of 17 cm and 1.3 dm. - Sea water
One tonne of seawater contains 25 kg of salt. How many tonnes of seawater needs to be evaporated to obtain 1 tonne of salt? - Study
For 7 hours of study, she scored a 75, so if she made 93, how many hours would she need to study? - Flowerbed
The flowerbed has a length of 3500mm and a width of 1400mm. How much foil is needed to cover the flowerbed? How many m² of foil was consumed for its production (add 10% of the material to the joint and waste)? How many liters of air is inside the enclosur - Surface area Calculate the surface area of a four-sided 2-m high prism whose base is a rectangle with sides of 17 cm and 1.3 dm.
- The tram
The tram is moving with acceleration a = 0.3 m/s2. How long will it pass the first meter of the track? How long does it take 10 meters? What is its speed at the end of the 10-meter track? - Magic belt
The magic rectangular belt has the property that whenever its owner wants something, the length of the belt is reduced to 1/2 and the width to 1/3. After three such wishes, the belt had an area of 4 cm². What was its original length if the original width - Photo egative
Negative dimensions are 36mm and 28mm. What will the photo size be in the 21:4 ratio? - Tablet schedule
It is Monday at 10 a.m. Luboš has returned from the doctor, who prescribed him tablets: he will take the first one immediately, the next two days he will take them after six hours, and the rest after eight hours. When will Luboš collect all the tablets if - Water reservoir
The water tank has a cuboid with edges a = 1 m, b = 2 m, and c = 1 m. If we fill fifteen 12-liter cans, how many centimeters of water will fall? - Painting
To paint the pool with dimensions: 2 meters depth, 3 m x 4 m we bought paint to 50 meters square. How much "paint" will be wasted? - Sales of products
For 80 pieces of two quality products, the total sales are 175 Eur. Suppose the first quality product was sold for n EUR per piece (n natural number) and the second quality product after 2 EUR per piece. How many pieces of the first quality were sold?
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