Math practice for 13 year olds - page 255 of 428
Number of problems found: 8557
- Two pipes
How long will the pool be filled with a double supply pipe if it takes the pool to fill the first pipe by 4 hours long and the second pipe 9 hours longer than both pipes open simultaneously? - 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. - Two airports
Two airports are 2690 km away. From the first airport, the airplane flies at a speed of 600 km/h, and from a second airplane at a speed of 780 km/h. When will they meet if they fly at 10:00? How far from the first airport? - Simple equation 6
Solve the equation with one variable: X/2+X/3+X/4=X+4 - 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 - 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 meters. A beet seedling occupies 20 square centimeters, and a parsley seedling occupies 10 square centimeters. He started by planting beets in rows, and the second row was always parsley. He alternated the r - Trip to a city
Lin wants to save $75 for a trip to the city. If she has saved $37.50 so far, what percentage of her goal has she saved? What percentage remains? - Parallelogram
Rhomboid (parallelogram) has a longer side of 50 cm long. The size of its one height is four times the size of its second height. Calculate the length of the shorter side of this rhomboid in centimeters. - Octagonal tank
The tank has the shape of a regular octagonal prism without an upper base. The base edge has a = 3m, and the side edge b = 6m. How much metal sheet is needed to build the tank? Do not think about losses or sheet thickness.
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