Math practice for 13 year olds - page 251 of 415
Number of problems found: 8281
- Circular arc length
The length of the circular arc at the corresponding angle of 120 ° is 8 cm. What is the size of the whole circle? What is its radius? - Workshops
The first workshop will complete the robot itself in 15 days, and the second workshop in 10 days. They started together, but only the second workshop worked after three days. Thus, the work will take 15 days. - Two pipes
How long will it take to fill the pool using both supply pipes if the first pipe alone fills it in 4 hours and the second pipe takes 9 hours longer than both pipes running together? - Oven carrying weight
The inner radius of the oven is r1 = 15cm, the outer radius is r2 = 20cm, and the length is 227cm. Can one person take it if its material density is 2.8 g / cm cubic? - Inquality
Solve inequality: 3x + 6 > 14 - Container diameter calculation
What is the diameter of a cylindrical container if half a liter of water reaches a height of 12 cm? - Pool pump filling
At the swimming pool, they use three pumps with the same output to fill the pool and fill the pool in 6 hours. How long does it take for the pool to fill nine pumps? - Divide 5
Divide number 288 by the following ratio of 3:4:5. - Simple equation 6
Solve the equation with one variable: X/2+X/3+X/4=X+4 - At a party
At a party 12 guests left their shoes in the hallway. In total there were 6 pairs of men's shoes, 6 pairs of women's shoes, 6 pairs of brown shoes, 6 pairs of black shoes. After the party it was found that some of the shoes had disappeared. 5 men's and 5 - Bicycle wheel turns
The pedal wheel on a bicycle has 28 teeth. The gear wheel on the rear wheel has 8 teeth. How many times does the rear wheel turn if we step on both feet 112 times? How many meters can we travel with it at least, and how much more if the rear wheel has a d - Gas Air Weight Ratio
One m³ of air weighs 13/10 kg, and the same volume of natural gas weighs 4/5 kg. How many times lighter is the gas than air? - One trapezium
One trapezium has AB=24M, BC=36M, CD=80M, DA=80M long sides. Find the area. - Prime inequality solutions
How many prime numbers are the inequality solutions: x / 3> x - 8? - Iron density Calculate the weight of a 2 m long rail pipe with an internal diameter of 10 cm and a wall thickness of 3 mm. The iron density is p = 7.8 g/cm³.
- Perfect cubes
Suppose a number is chosen at random from the set (0,1,2,3,. .. ,202). What is the probability that the number is a perfect cube? - Opposite direction distance
A pedestrian and a cyclist left the town of S simultaneously but in the opposite direction. Pedestrian at 4.4 km/h, cyclist at 18 km/h. How far apart are they after 1 hour and 42 minutes? - Cyclist catches pedestrian A pedestrian left town S at a speed of 4.2 km/h. After 1 hour and 10 minutes, a cyclist left the same city and in the same direction at a speed of 18 km/h. After how many minutes does the cyclist catch up with the pedestrian, and how far from town S?
- Cyclist meeting distance A cyclist leaves town A, 84 km from town B, and 2 hours later, another cyclist goes from town B to town A at the same average speed of 14 km/h. How far from city B will they fight?
- Grandfather 3
Grandfather bought a square field of 900 square metres. A beet seedling occupies 20 square centimetres, and a parsley seedling occupies 10 square centimetres. He started by planting beets in the first row, with every second row planted with parsley. He al
Do you have unsolved math question and you need help? Ask a question, and we will try to solve it. We solve math question.
