Math practice for 13 year olds - page 321 of 428
Number of problems found: 8549
- Pharmacy
The pharmacy adds 3 liters of 95 percent alcohol and 5 liters of 38.04 percent alcohol. How much percent alcohol did the pharmacy get? - Water temperature
Mom is going to wash by hand in water that should be at 40°C. The tub already has 10 liters of water at a temperature of 12.3°C and can still hold 5 liters. What temperature should the water be allowed to be? - Factorial equation
Solve the equation: x!: 5 = 1008 The solution to the equation is a natural number. - Security
The safe's security code is set with three dials. The first dial has five different letters, the second dial has the numbers 0 to 4, and the third dial has the numbers 5 to 9. One code can be set in approximately 1 second. How should the alarm be timed so - Car speeds
A truck left Beroun at 7 o'clock in the direction of Prague on the highway in the fog. In 20 minutes after that, a car drove by at the same place and along the same route at a 27 km/h higher speed. The passenger car overtook the truck after another twenty - Time gone
The Square of Richard's age equals the age of his mother. When he is two times older, his mom will be seven times older than him. Thus, Richard and his mom are seven times older. - Right triangle eq2
The hypotenuse of a right triangle is 9 cm longer than one leg and 8 cm longer than the second leg. Determine the circumference and area of a triangle. - Catching up
Peter and Karel live at the same address. Peter will drive to the stadium in 30 minutes and Karel in 40 minutes. If Karel goes 5 minutes early, where will Peter catch up? - Oat bags
The cowboy will give the sheriff two bags of oats, and the sheriff will have 2x more bags than the cowboy. If the sheriff gives two bags of oats to the cowboy, they will both have the same. How many bags does each have? - Class arrangements
There are 4 classrooms on the ground floor of the school building, which are numbered 1,2,3,4. First-year students A, B, C, and D will be placed in these classrooms. Write all possible class arrangements and their number. Thank you - Orchard trees
Calculate how many trees are in an orchard if you know that 5/12 orchards consist of apple trees, 1/6 plums, and 1/60 walnuts. The remaining 30 trees are pear trees. - Train speed
A train running at 20 m/s sees passengers through the window for 5 seconds. Another train with a length of 250 m runs on the siding in the opposite direction. Find the speed of the second train. - Book profit
How much more expensive is it for the owner to sell a book he bought in an antiquarian book for half the price if he sells it for two-thirds of the original price? - Three colors 2/3
Marek has balls of three colors. Two-thirds of the balls are green, 2/7 are blue, and one ball is yellow. How many balls does Marek have? - Class students
3/4 of the class went skiing. Of those who stayed home, 1/3 fell ill, and the remaining 6 were at a math camp. How many students does the class have? - Volume of an apple
How many apples will fit in a box measuring 20 cm × 50 cm × 25 cm? - Triangle arm
There is an isosceles triangle with a circumference of 36 cm, and the height at the base is 12 cm long. Calculate the length of the arm of a given triangle. - Percent to number
To increase that number by 5 percent, we need to multiply it by: - Triangle perimeter
The area of an equilateral triangle is 81 times three below the square root of cm². Calculate its circumference. - The pipe
The pipe is 1.5 m long. Its outer diameter is 60 cm, inner diameter is 52 cm. Calculate the pipe's weight if the material's density from which it is made is 2 g/cm³. Please round the results to whole kilograms.
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