Math practice for 13 year olds - page 335 of 413
Number of problems found: 8260
- Rain probability
In recent years, it has rained 12 days in March. What is the probability that it rained on March 18? - Catheti
One of the catheti of the right triangle has a length of 12 cm. At what distance from the center of the hypotenuse is another leg? - Water solution
How many grams of salt should we dissolve in 400 g of water to get a 20% solution? - Triangle sides
Calculate the size of the sides and angles of the triangle ABC if you know vc = 28, α = 51°19', β = 67°38'. - Trees
A certain species of tree grows an average of 0.5 cm per week. Write an equation for the sequence that represents the weekly height of this tree in centimeters if the measurements begin when the tree is 200 centimeters tall. - 6 terms
Find the first six terms of the sequence. a1 = 7, an = an-1 + 6 - Timber log
The ship goes from point x to y. Downstream it takes 4 hours, and upstream 6 hours. How long does it take from a point x to y a log? - Donuts
In the dining room, Thomas, Philip, and Martin sit at one table. Together, they eat 36 doughnuts. Philip ate twice as much as Thomas, and Martin ate half more than Philip. How many doughnuts did each eat? - Cyclist speed
A cyclist covered a track of 40 m in 5 s. The first section of the 30 m track was covered in 3 s; the remaining section was covered in 2 s. Specify: a) the average speed of the cyclist on the first section of the track b) the average speed of the cyclist - Cuboid - volume, diagonals
The length of the one base edge of cuboid a is 3 cm. The body diagonal is ut=13 cm, and the diagonal of the cuboid's base is u1=5 cm. What is the volume of the cuboid? - Speedboat and train
At 12:15, a train speeding 55 km/h left the station. Twelve minutes later, an 80 km/h speedboat set off behind the train. What time does the express train catch up? How far from the station? - Isosceles trapezoid
In an isosceles trapezoid KLMN, the intersection of the diagonals is marked by the letter S. Calculate the area of the trapezoid if /KS/: /SM/ = 2:1 and a triangle KSN is 14 cm². - Height ratio
In a general triangle, the aspect ratio a: b = 2:3. What is the ratio of heights va: vb? - Republic
First, guess which circle has the larger diameter: the one with the same area as the area of the Czech Republic, or the one with a circumference equal to the length of the border of the Czech Republic? Then check your guess by calculating. The area of the - Circular ring
A square with an area of 16 centimeters is inscribed circle k1 and described to circle k2. Calculate the area of the circular ring, which circles k1, and k2 form. - Garden on map
On a map with a scale of 1:5000, the grandfather's garden is represented by a rectangle measuring 4 cm and 3 cm. What dimensions will it have on a map scale of 1:4000? - Number calculation
Find a number from which 5% is as many as 7% out of 45. - Money for grandchildren
My grandfather distributed CZK 1,600 among his grandchildren. He divides the amount proportionally to their ages. The grandchildren are 15, 12, and 6 years. How much will each of the boys get? - Scout trip
During the trip, the scouts ran 1/2 of the route on the first day, 2/5 of the route on the second day, and on the third day, they were still 12 km away. How many km have they traveled in all three days? - Trapezoid waste
We cut two triangles from the rectangular plate so that the resulting quadrilateral-trapezoid with the same arm lengths has an area of 32 cm², and one of its bases is twice as long as the other. What is the area of the two triangles that make up the waste
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