Math practice for 13 year olds - page 68 of 434
Number of problems found: 8670
- Through 82036
5 m³ of water flows through the pipe in 1 second at a maximum speed of 2 m/s. What is the pipe radius?
- Suspicion 82035
At the time of the theft, there were 96 people in the hotel; 61 were beyond suspicion. Of the 47 employees at the hotel, 23 are beyond suspicion. How many guests are not beyond suspicion?
- Together sewing
Eva sews a costume in 6 hours, Ivana in 8 hours, and Monika in 4 hours. How long will it take them to make the costume if they work together?
- Repetition: 82003
Calculate how many different monograms (short name and surname) I can make from the letters A, E, M, Z, and K. a) with repetition: b) without repetition:
- Nationalities 81998
In the popular Italian resort of Caorle, there are only 4 nationalities. The resort has 3/20 Germans, 2/5 Czechs, 1/4 Austrians, and 500 Brits. How many tourists are there in total at the resort?
- Afforestation 81997
During afforestation, two workers planted 80 seedlings in 2 hours. At the same output, how many seedlings did 6 workers plant in 5 hours?
- Position 81987
Find a number with six digits. If you put the last digit before the first, you get a new number that is five times larger. The digits between must not change their position.
- Diameter of barrel
A garden barrel that is 1 m high has a base with a diameter of 80 cm. How many liters of water can fit in the barrel?
- Volunteers 81981
Volunteers planted saplings in the forest nursery; spruces made up 55% of all saplings; one-third were edible, and the rest were young pines. How many saplings did they plant if the number of saplings was greater than 1060 and less than 1090?
- Together 81979
Three friends split the reward in the ratio of 3:5:7. One of them received exactly €49. How many euros did they get together?
- Together 81974
Two gears mesh together. The larger wheel has 56 teeth, and the smaller wheel has 20 teeth. How many times does the smaller wheel turn if the larger wheel turns 15 times?
- Divided 81973
A log 88 cm long is divided into 3 parts in the ratio 3: 2: 5. How big is each part?
- Passenger train
At 9:15 AM, a passenger train passes the station at a speed of 75 km/h. At 10 o'clock, an express train passes through the same station in the same direction at a speed of 120 km/h. Both trains arrive at the same destination station at the same time. a) a
- Probability 81964
Calculate the probability of the event that you sit in seats 1 to 30 in the cinema at: a) seat marked with a prime number b) seat marked with an even number c) a seat marked with a number divisible by 3 or 4
- Staircase 81963
How long is the staircase railing with 17 steps if the step is 32 cm deep and 14.5 cm high? The last step does not count.
- Dimensions 81957
How many bricks are needed to build a wall that is 12 m long, 1.6 m high, and 47 cm wide if the dimensions of the brick are 30 x 15 x 7.5 cm and 5% of the wall volume is mortar?
- We randomly
We randomly select a three-digit number. What is the probability that the number 8 occurs at most once in its notation?
- Competition 81952
All three team members took turns fulfilling the competition task without delay. The first member used up 30% of the total competition time. The second needed 10 minutes more than the first, and only 10 minutes remained for the third. What % of the total
- Calculate 81950
The tangent of the angle formed by the adjacent sides of the triangle ABC (side a=29 m, b = 40 m) equals 1.05. Calculate the area of that triangle.
- Inscribed cube
A cube is inscribed in a sphere with a radius of 27 cm. Calculate its volume and surface area.
Do you have unsolved problem that you need help? Ask a question, and we will try to solve it. Solving math problems.