Harder math problems
- Toys
3 children pulled 6 different toys from a box. How many ways can toys be divided, so each child has at least one toy?
- Pool
If water flows into the pool by two inlets, fill the whole for 19 hours. The first inlet filled the pool 5 hour longer than the second. How long does the pool take to fill with two inlets separately?
- Rectangular cuboid
The rectangular cuboid has a surface area 5334 cm², and its dimensions are in the ratio 2:4:5. Find the volume of this rectangular cuboid.
- Sphere
The sphere's surface is 12100 cm², and the weight is 136 kg. What is its density?
- Axial section
The axial section of the cone is an equilateral triangle with an area 208 m². Calculate the volume of the cone.
- Numbers
Determine the number of all positive integers less than 4183444 if each is divisible by 29, 7, 17. What is its sum?
- Rectangle
In a rectangle with sides, 8 and 9 mark the diagonal. What is the probability that a randomly selected point within the rectangle is closer to the diagonal than any side of the rectangle?
- Tetrahedral pyramid
Calculate the volume and surface area of a regular tetrahedral pyramid, its height is $b cm, and the length of the edges of the base is 6 cm.
- Pumps
The tank is filled with two pumps in 16 minutes. The first pump is filled in 30 minutes earlier than two one. How many minutes is filled with the first pump?
- Crystal
The crystal grows every month 1.2 permille of its mass. How many months to develop a crystal from weight 177 g to 384 g?
- Raffle
In the pool number from 1 to 115. What is the probability that a randomly selected number is not a prime number?
- Triangle SAS
Calculate the triangle area and perimeter if the two sides are 105 dm and 68 dm long and angle them clamped is 50 °.
- Rectangle - sides ratio
Calculate the area of a rectangle whose sides are in ratio 9:14 and perimeter is 388.
- Workers
Two workers, A and B, will be done work together for 15 days. They worked together for 13.5 days. Then A worker became ill, and worker B finished the job alone for 7.5 days. If every worker was working alone, how many days took the whole work for workers
- Shooters
In the army, regiments are six shooters. The first shooter target hit with a probability of 49%, next with 75%, 41%, 20%, 34%, 63%. Calculate the probability of target hit when shooting all at once.
- TV fail
The TV has average 35 failures after 10,000 hours. Find the probability of TV failure after 400 hours of operation.
- Mast
Mast has 13 m long shadow on a slope rising from the mast foot in the direction of the shadow angle at angle 13.3°. Determine the height of the mast if the sun above the horizon is at an angle 45°12'.
- Rotation
The right triangle with legs 11 cm and 18 cm rotates around the longer leg. Calculate the volume and surface area of the formed cone.
- Sales
From statistics of sales goods, item A buys 51% of people, and item B buys 59% of people. What is the probability that from 10 people buy 2 item A and 8 item B?
- Cylinder - basics
Cylinder with base radius r = 54 cm and height h=35 cm. Calculate: a) Area of the base
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