Math practice for 13 year olds - page 82 of 414
Number of problems found: 8262
- Grandson uncle age
The grandson is 11 years old, and the uncle is 59. In how many years will the uncle be 3 times as old? - Paper strip folding
A rectangular strip of paper measuring 4 cm x 13 cm is folded as shown. The two resulting rectangles have areas P and Q, where P = 2Q. Calculate the value of x. Note divide the side of 13 cm by x and 13-x. - Lenka book library
Helen has 30% fewer books in her library than Philip but 40% more than Ivan. Philip has 250 books. How many books does Ivan have? - Student grade percentage
There are 32 students in the class; 17 are awarded, 14 passed, and 1 failed. Determine the number percentages of students with honors, successful and not successful students - Cone sphere volume
A sphere is inscribed in an equilateral cone with a base diameter of 12 cm. Calculate the volume of both bodies. What percentage of the volume of the cone is filled by the inscribed sphere? - Men money denarii
Two men talk about how much money each has. The first says to the second: If you give me 12 denarii, we will both have the same. "Second branch: If you give me 12 denarii, I will have ten times more than you. How many denarii did each of them have? - Cylinder diameter height
A cylinder has the same diameter as its height. Calculate these data if the surface is 200 cm². Report the results to the nearest millimeter. - Girls pocket money Zuzana, Anna, and Eliška receive pocket money every month. They donated part - Zuzana 40%, Anna 50% and Eliška CZK 195. If we add up all 3 amounts and divide the sum by 3, the result will correspond to 4/9 of the pocket money of each of the girls. What is
- Companies 3
Companies supplying electricity to households used two rates. In 1996, the price for 1 kWh was 1.10 CZK and the night rate was 0.46 CZK per kWh. In 1997, these rates were 1.28 CZK and 0.53 CZK respectively. Express the ratio of the standard rate to the ch - Airplane distance meeting
Two points are at a distance of 1840 km. An airplane departs from A at 7:00 a.m. and flies at an average speed of 50 km/h faster than another airplane departs from B at 8:00 a.m. At what distance from A do they meet at 9:00? - Salary increase percentage
Since starting the job, Jiri's salary has doubled. By what percentage did his salary increase? - 200 students
200 students sat exams in Czech, mathematics, and physics. 114 students passed Czech, 50 passed mathematics, and 41 passed physics. 14 students passed both Czech and mathematics, 15 passed both mathematics and physics, and 11 passed both Czech and physics - Cone side length
Calculate the length of the side of the cone; they rounded the result to tenths of a millimeter. If you know: radius 24 mm and height 46 mm - Antifreeze
A car owner needed to replace the antifreeze liquid in the radiator. On the label of the low-freezing liquid it was stated: volume parts of low-freezing liquid 2, volume parts of distilled water 1, freezing point -20°C. How many litres of low-freezing liq - Polygon angle ratio
In a certain polygon, the ratio of the sum of the sizes of its internal angles and the sum of the sizes of the complementary angles is 2:5. How many vertices does this polygon have? - Matěj Lojza marbles
Matthew has 2 more marbles than three times the number of marbles that Louis. Both together have 18 balls. How many marbles does Louis have? - Triangle angle ratio
In the right-angled triangle ABC (the right angle at vertex C), the angle ratio is α : β = 5 : 3. Calculate the sizes of these angles and convert them to degrees and minutes (e.g., 45°20') - Father son ratio The father is older than the son by the ratio of 5:2. Dad is older than 33. How old are they both?
- Quadrilateral and angles
In a quadrilateral, angle α is twice as large as angle β. Angle γ is 80% of angle α, and angle δ is 30° greater than angle α. Determine the angles of this quadrilateral. - Percentage - fence
We are painting a wooden fence. On the first day, we painted one-half of the fence. The next day, we painted half of the remaining part. On the third day, again, half of the remaining part. After the third painting, we had 12.5 meters of unpainted fence l
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