Math practice for 13 year olds - page 329 of 413
Number of problems found: 8260
- Equation solutions
The solution to the equation 3x = 8x is a / no real number b / x = 8/3 c / x = 3/8 d / x = 0 e / infinitely many solutions - Grandmother
A grandmother wants to divide candies among her grandchildren. If she gives five candies to each, she is three short. If she gives four candies to each, she has three left over. How many grandchildren does she have, and how many candies does she have? - Pool whitewashing
The pool is in the shape of a vertical prism with a bottom in the shape of an isosceles trapezoid with dimensions of the bases of the trapezoid 10 m and 18 m, and arms 7 m are 2 m deep. During spring cleaning, the bottom and walls of the pool must be whit - Toothpaste duration
A full tube of toothpaste is enough for one family member for six weeks. How long will three family members last? - Workers needed
Twenty-seven workers did the work in 12 days. In how many days would nine workers do the same job? - Working time If work is done in 16 days at a 10-hour shift, how many days will it be done at 8-hour shifts?
- Tree height
A tree with an unknown height casts a shadow 18 m long at a time, while a two-meter pole casts a shadow of 2.4 m. How tall is the tree? - Seawater salt
By evaporating 15 kg of seawater, we get 517.5 g of salt. How much seawater do we need to obtain 3.45 kg of salt? - Cone
Calculate the volume of the rotating cone with a base radius of 26.3 cm and a side 38.4 cm long. - PIN attempts
How many attempts do I need to guess the 3-digit PIN to be sure I can guess it? - Pool inlets
At the swimming pool, they usually use three tributaries with the same power to fill the pool. Then the pool will fill in 5 hours. How many hours less would it take to fill the pool if they added 2 more inlets with the same capacity? - Two-digit numbers
Write all the two-digit numbers that can be composed of the digit 7,8,9 without repeating the digits. Which ones are divisible b) two, c) three d) six? - Original reduce
If we reduce the unknown number by 469, we get 65% of the original number. What is the original number? - Petrol consumption
Two identical cars use 12 l of petrol to cover 150 km. How much gasoline do 25 similar cars use per 1800 km? - Well digging cost
The width of the well with the masonry should be 1.8 m. How much will digging a well 16 m deep be paid if an average of 800 CZK is paid from meter cubic? - Dog food
The shelter buys a supply of food for 12 dogs for one week. How many days will this supply last if two more dogs are added to the shelter? - The tent
The tent shape of a regular quadrilateral pyramid has a base edge length of a = 2 m and a height of v = 1.8 m. If we have to add 7% of the seams, how many m² of cloth did we need to make the tent? How many m³ of air will be in the tent? - Cube walls
Find the volume and surface area of the cube if the area of one wall is 40 cm². - Five pumps
Three same pumps fill the tank with 50400 liters of diesel in 7 hours. How many liters of diesel will it take in 4 hours if we add two more of the same pumps and pump them the same way? How much more (or less) will they get if we add 2 of the same pumps a - Copper wire
What is the weight of 1000 m copper wire with a diameter of 5 mm when metric density p = 8.8 g/cm³?
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