Math practice for 13 year olds - page 220 of 415
Number of problems found: 8281
- Reservoir - spherical
The reservoir is a sphere with a diameter of 12 m. If it is painted twice, how many kg of paint is needed to paint it, and one kilogram is enough to paint about 8 m²? - Triangle revolution volume
What is the hole volume drilled by the drill in the shape of a right triangle that revolves around a longer perpendicular? The perpendiculars of the triangle are 10 cm and 3 cm long. - Class student calculation
How many students are in the class when 54% have both parents at work? Employed parents have 20 students. - Kite rhombus calculation
The dragon is shaped like a diamond. Its diagonals are 60 cm and 90 cm long. Calculate: a) side of the rhombus b) how much paper do we need to make the kite? If we need to stick it on both sides, it needs 5% of the total area of the paper to bend. - Pocket money savings
Zuzana receives pocket money from her parents. In October and November, she managed to save 288 euros. The ratio of money saved for October and November is 5:4. How many euros did Zuzana save in October, and how much in November? - Dwarf fairy calculation
There were 3 dwarves more than fairies in the forest kingdom. A drought hit the kingdom, and a quarter of the dwarves and one fairy left. The king thus reduced the number of dwarves and fairies in the kingdom to 3. How many fairies and dwarves were there - Diamond circumference calculation
In the diamond ABCD, the angle BAD is 60°; the length of the diagonal BD is 7 cm. Calculate the circumference of the diamond. - Block dimension ratio
The block's dimensions are in the ratio 16:12:8, and the sum of these dimensions is 240 decimetres. What are the dimensions of the block? - Math grade distribution
From the quarterly work in mathematics in the eighth grades, 1/3 of all pupils got a one, 2/7 of all pupils got a two, 5/8 of the rest got a three, 8 pupils got a four, and 4 got a five. How many students wrote a paper? How many got a one, a two, and how - Betting winnings division
Frank and Robert bet €8 on the result of a football match. Frank contributed €3.60 and Robert the rest. To their surprise, they won €60. How should they divide the collected money fairly? - Water mixing
We mix 2 liters of water at 100 degrees Celsius warm and 18 liters of water at 32 degrees Celsius warm. What temperature will the water have after mixing? - Briefcase code options
Ferko received a briefcase with an adjustable three-digit code for his birthday. How many options do you have to set the code if you like a number with two sevens? - Shareholders and profit
The company distributed the profit among the shareholders in the ratio of 2:3:4:7. What was the total profit in the company if the last shareholder received € 1,400? - Stream cleanup calculation
The scouts decided to clean up the stream outside the town. On the first day, they cleared half of the total length of the stream. On the second day, 2/7 of the entire length. On the third day, they cleared a third of what was left, and on the fourth day, - Pancake baking calculation
Mom baked pancakes and put them on a plate. After Mike had eaten three-sevenths of them, his brother Pete came and took three-quarters of the pancakes from the plate. In the end, Jane finished the remaining 7 pancakes. How many pancakes did mom bake? - Copper heat calculation
What heat do we need to supply a copper body weighing 8 kg to raise its temperature by 136 degrees Celsius? - Triangle base calculation
They make bases for table lamps from bronze in the shape of an isosceles triangle. How many m² are needed for 5 mats if the arms are 24 cm long and the height to the triangle's base is 1.5 dm? - Pyramid volume calculation
Calculate the volume of a regular quadrilateral pyramid, which has the size of the base edge a = 8 cm and the length of the side edge h = 9 cm. - Chocolate purchase calculation
The kindergarten purchased 40 chocolates of two types. Dairy is sold after 16 CZK per piece, and hazelnut after 11 CZK per piece. They paid a total of CZK 565. How many chocolates were there? - Tank water remaining
They drained the water from the full tank through three holes. 1/6 of the tank volume flowed through the first hole, 2/5 of the volume through the second hole, and 1/4 of the volume through the third hole. The tank has the shape of a cuboid with dimension
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