Harder math problems

Pool
Water flows into a pool through two inlets and fills it in 5 hours. If the first inlet alone takes 5 hours longer than the second inlet alone, how long does each inlet take to fill the pool on its own?
Rectangular cuboid
The rectangular cuboid has a surface area 4131 cm², and its dimensions are in the ratio 2:4:5. Find the volume of this rectangular cuboid.
Axial section
The axial cross-section of a cone is an equilateral triangle with an area of 208 km². Calculate the volume of the cone.
Sphere
A sphere has a surface area of 21000 cm² and a mass of 73.2 kg. What is its density?
Rectangle
In a rectangle with sides 8 and 9, a diagonal is drawn. What is the probability that a randomly selected point inside the rectangle is closer to the diagonal than to any side of the rectangle?
Triangle SAS
Calculate the area and perimeter of a triangle if two sides are 46 m and 33 m long and the angle between them is 170°.
Crystal
The crystal grows every month at 1.2 permille of its mass. How many months does it take to develop from weight 177 g to 384 g?
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?
TV fail
On average, a television set experiences 25 failures per 10,000 hours of use. Find the probability of a failure occurring within 400 hours of operation.
Pumps
A tank is filled by two pumps working together in 23 minutes. The first pump alone fills the tank 37 minutes faster than the second pump alone. How long does it take the first pump to fill the tank on its own?
Mast
A mast casts a shadow of length 16 on a slope that rises from the base of the mast in the direction of the shadow at an angle of 9.7°. Determine the height of the mast if the sun is at an angle of 40°48'° above the horizon.
Rotation
A right triangle with legs 11 cm and 18 cm is rotated around the longer leg. Calculate the volume and surface area of the cone formed.
Raffle
In the pool number from 1 to 109. What is the probability that a randomly selected number is not prime?
Shooters
In a regiment there are piati shooters. The first shooter hits the target with a probability of 42%, and the next with 40%, 21%, 58%, 67%%. Calculate the probability that the target is hit when all shooters fire simultaneously.
Sales
From statistics of sales goods, item A buys 77% of people, and item B buys 58% of people. What is the probability that from 15 people buy 8 item A and 7 item B?
Numbers
Determine the count of all positive integers less than 4064028 that are divisible by 5, 23, 2. What is their sum?
Workers
Two workers, A and B, will be done work together for 10 days. They worked together for 8 days. Then A worker became ill, and worker B finished the job alone for 6 days. If every worker worked alone, how many days did the whole work take for workers A and
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 6.2 km/h, you come to the station 52 minutes after leaving the train. If you bike to the station at speed 23 km/h, you come to the station 51 minutes before its departure. How far is the train station?
Earth parallel
The Earth's radius is 6377 km. Calculate the circumference of the parallel at latitude 75°.

1
2
...
4
5
»

Do you have unsolved math question and you need help? Ask a question, and we will try to solve it. We solve math question.