New math problems
- Boys and girls
There are eight boys and nine girls in the class. There were six children on the trip from this class. What is the probability that left a) only boys b) just two boys
- Car crash
On the road, with a maximum permitted speed of 60 km/h, there was a car crash. From the length of the vehicle's braking distance, which was 40 m, the police investigated whether the driver did not exceed that speed. What is the conclusion of the police, as
- Two numbers 7
The sum of two consecutive even numbers is 30. Find the numbers.
- AP RT triangle
The length of the sides of a right triangle form an arithmetic progression, longer leg is 24 cm long. What are the perimeter and area?
- KLMN trapezoid
In the KLMN trapeze, KL has a 40 cm base and an MN of 16 cm. Point P lies on the KL line so that the NP segment divides the trapezoid into two parts with the same area. Find the length of the KP line.
- The publisher
The publisher prepares the release of the dictionary. Print preparation costs no matter the number of printed copies of 150000 CZK. The printer charges 80 CZK for one print. A) What are the costs of one dictionary if 5000 copies printed? B) For what numb
- Five pupils
Five pupils clean 30 chairs one hour before four pupils. How many chairs clean one pupil in 1 hour?
There are 32 trees of three species in the orchard. 25% cherries, three eighty pears, others plums. How many plums are in the orchard?
- Diagonals of pentagon
Calculate the diagonal length of the regular pentagon: a) inscribed in a circle of radius 12dm; b) a circumscribed circle with a radius of 12dm.
- Sss triangle
Calculate the area and heights in the triangle ABC by sides a = 8cm, b = 11cm, c = 12cm
- Dance ensemble
The dance ensemble took the stage in pairs. During dancing, the dancers gradually formed groups of four, six and nine. How many dancers have an ensemble?
- The tourist
The tourist traveled 190km in 5 hours. Part of the journey passed at 5 km/h. The rest he went by bus at a speed of 60 km/h. How long has a bus gone?
- On the trip
On the trip were more than 55 children, but less than 65 children. Groups of 7 could be formed, but groups of 8 no. How many children were on a trip?
- The quotient
The quotient of g and 55 is the same as 279. What is g?
- Linear system
Solve a set of two equations of two unknowns: 1.5x+1.2y=0.6 0.8x-0.2y=2
Calculate the length of the pavement that runs through a circular square with a diameter of 40 m if distance the pavement from the center is 15 m.
- Exchange rates
If the Canadian dollar appreciated by C$0.005 relative to the US dollar, what would be the new value of the Canadian dollar per US dollar? Assume the current exchange rate was US$1 = C$0.907.
- Two thirds
Find two-thirds of the number equal to two-thirds of 99
- Clock's gears
In the clock machine, three gears fit together. The largest has 168 teeth, the middle 90 teeth, and the smallest 48 teeth. The middle wheel turns around its axis in 90 seconds. How many times during the day do all the gears meet in the starting position?
- Double 5
Peter was thinking of a number. Peter doubles it and gets an answer of 8.6. What was the original number?