Math practice for 13 year olds - page 56 of 435
Number of problems found: 8682
- Dimensions 83226
Calculate the weight of an iron bar 1.2 m long, whose cross-section is a trapezoid with dimensions a=10 cm c=8 cm and the distance between the bases v=6 cm. As we know, 1 cubic meter of iron weighs 7800 kg. - Painter 83225
A painter needs to mix yellow and red paint in a ratio of 3:7. How many liters of red paint must he add to 21 liters of yellow paint? - Percentage 83218
The tractor operator plans to plow a 24 ha (ha=hectare) field. He already plowed 20.64 ha. What percentage has he already fulfilled the plan? - Actually 83215
The square-shaped plot actually covers an area of 81 ares. Maybe draw it in the village plan on a scale of 1:200. What will be the length of the side on the plan? - In a queue
There are cars and trucks in a queue in front of a toll gate. A truck is three times longer than a car. Calculate how many cars are in front of the car that has just arrived, if there is one truck among them, which is one eighth of the length of the queue - Liters 83211
We have 160 L of water at 67°C; how many liters of cold water at 18°C are needed to cool it to 39°C? - Families 83209
Coal for 15 families lasts 60 days. How many days will the coal last for 20 families?
- Construction 83208
An isosceles triangle ABY has a base AB of length 5 cm and an angle at the primary vertex of 50°. Write down the construction progress. - Workers 4
Workers in a workshop machined the same parts for three months. Their output increased so that each subsequent month they machined 10 percent more parts than the previous month. In the last month, they machined 484 parts. How many parts did they machine i - Kilograms 83204
Nine kilograms of bell metal contain 7 kg of copper, the rest of which is tin. How much copper and how much tin were used to cast five bells? Each of the two larger bells weighed 535kg, and each of the remaining three smaller ones weighed 286kg. - Weighing 83201
Bronze is an alloy of copper and tin in a ratio of 1:4. How much copper does a bronze piece of jewelry weighing 25 g contain? - Buy and sell
The selling price is 5.75 EUR, and the buying price is 4 EUR. By what percentage was the price increased? - Construct 83195
Two line segments of different lengths are given. Construct a circle k so that both line segments are its chords. - Seamstresses 83192
Three sewers sew 7 skirts in 15 hours. How many skirts can 2 seamstresses make in 50 hours? - Mathematics 83190
The number of students studying teacher studies in mathematics has decreased in the last twenty years in a ratio of 2:10. How many students are studying teacher studies now when twenty years ago there were 50?
- Percentages 83188
There are 10 bags displayed in the store, 2 of which have a hidden error. Buyers randomly choose one bag. Express in percentages the probability that they will buy the bag without a mistake. - Daffodils 83181
The spring bouquet consists of 13 daffodils and 8 tulips, and the other 30% are freesias; how many flowers are there in total? - Proportional 83174
For the lever to be balanced, the arms' lengths must be inversely proportional to the weight ratio of the weights suspended on these arms. Complete the data: 30 cm, 10 cm, 4 kg, and? kg. - Original model
When drying, the modeling mass loses 36% of its original volume. If the cube's volume is 5.12 dm³ after drying, what was the original length of the edge? - Apprentice 83169 The master gave the apprentice the task of dividing the 28 m long electric cable into two parts so that the second part was 2.5 times larger than the first. How long were the cable sections supposed to be?
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