Math practice for 13 year olds - page 67 of 422
Number of problems found: 8425
- One-twentieth 82239
Peter and Honzo decided to build the building as quickly as possible. They built one-twentieth of the building in ten minutes. After 20 minutes, three more friends joined. Everyone was building at the same pace. How many minutes did it take to build the s
- Capacity 82231
There were 60 people in the stadium, which was 30% of capacity. How many people can fit in the stadium?
- Two-hundred-liter 82230
What is the weight of a two-hundred-liter barrel with ethanol if the empty barrel weighs 50 kg?
- Centimeters 82219
What is the height of a box whose base edges are 50 mm long and 0 full six dm if its volume is 120 cubic centimeters?
- Acceleration 82217
The car has a speed of 5 m/s and accelerates to 35 m/s in 12 seconds. Calculate the acceleration of the car at a speed of 34.5 m/s.
- Trapezoid 82216
Given is an isosceles trapezoid ABCD with bases 10 cm and 14 cm. The height of the trapezoid is 6 cm. Determine the interior angles of the trapezoid.
- Construction 82214
At the construction site, the sand that belongs to the mortar is sifted through a sieve. At the same time, 1/6 of the coarse sand falls through. Determine how many m³ of sand must be brought in to obtain 2 m³ of sifted sand.
- Diameter 82212
How many meters of copper wire with a diameter of d=3 mm will be produced from 60 kg of copper scrap if the specific gravity of copper is p=9g/cm³?
- Dance party
At the dance party, the organizer discovered that 168 different dance pairs could be formed from girls and boys. How many boys are there at the dance if there are 12 girls?
- Excavators 82208
Two excavators dig a pit in 12 days. How much shorter will this job take if 8 excavators dig the hole? In 3 or 9 days?
- Segment 82178
If I reduce a segment of length 72 cm in a ratio of 5:8, how many cm will it be?
- Sun and shadow
The pole is stuck vertically into the ground. The protruding length is 1m. What is the length of the shadow cast when the sun is just 50° above the horizon?
- Hypotenuse and legs
A right triangle with hypotenuse c=25 dm is given. Calculate the length of the unknown side, given: side a=15 dm. Find the area of this triangle. Sketch the triangle and describe all its vertices and sides correctly.
- Increase 82151
Increase 380 by 28%
- Operation 82150
In 24 hours, the engine consumes 346 I of gasoline. How many liters does it consume in 126 hours of operation?
- Supply 82149
The water supply is enough for 12 horses for 16 days. How many horses will this supply of water last for 12 days?
- Determine 82148
If we reduce the unknown number by 24%, we get the number 358. Determine the unknown number.
- Quadrilateral prism
Calculate the volume and surface area of a regular quadrilateral prism with base edge a=24 cm if the body diagonal makes an angle of 66° with the base.
- Determine 82143
Determine the size of the interior angles in an isosceles triangle if you know that the angle opposite the base is 15° greater than the angles at the base.
- Fifteen 82121
The father is five times older than the son. The father will be twice as old as the son in fifteen years. How old is Dad now?
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