# Harder math problems

- Pool

If water flows into the pool by two inlets, fill the whole for 20 hours. The first inlet filled the pool 8 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 2080 cm², and its dimensions are in the ratio 4:1:5. Find the volume of this rectangular cuboid. - Axial section

The axial section of the cone is an equilateral triangle with an area 208 m². Calculate the volume of the cone. - 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?

- Sphere

The sphere's surface is 12100 cm², and the weight is 136 kg. What is its density? - 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? - 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 °. - 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? - TV fail

The TV has average 30 failures after 10,000 hours. Find the probability of TV failure after 300 hours of operation.

- Numbers

Determine the number of all positive integers less than 5286382 if each is divisible by 19, 5, 23. What is its sum? - Pumps

The tank is filled with two pumps in 16 minutes. The first pump is filled in 30 minutes earlier than the second one. How many minutes is filled with the first pump? - 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. - Raffle

In the pool number from 1 to 115. What is the probability that a randomly selected number is not a prime number?

- 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. - 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? - 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 - Dices

We will throw two dice. What is the probability that the ratio between numbers on the first and second dice will be 1:2? - Motion

If you go at speed 5.5 km/h, you come to the station 33 minutes after leaving the train. If you bike to the station at speed 29 km/h, you come to the station 52 minutes before its departure. How far is the train station?

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