Math practice for 13 year olds - page 257 of 422
Number of problems found: 8427
- Minutes 7177
The tank holds 140 liters of water. It is filled with a tap in 5 minutes, and the drain is emptied in 7 minutes. How long will it take for the empty tank to fill if we open the faucet and drain it? - Cube surface and volume
Find the surface of the cube with a volume of 27 dm³. - Soup from canteen
For how many people is 90 liters of soup enough if we assume 3/8 liters of soup per person in the canteen? - Inlet and outlet
The pool has a capacity of 50 hl. The inlet pipe flows in 1 minute 1.25 hl, and the waste pipe outlet drains the full pool in 50 minutes. How long will it take to empty the entire pool when both the inlet and outlet are opened simultaneously? - Butter
The same amount of butter is cut evenly from a cuboid every day. In seven days we used so much butter that all its dimensions were halved. a) How much percent of butter do we still have left? b) How many days will the butter last if we continue to cut the - Kilometers 7161
Peter cycled 24 kilometers on the weekend, twice as many on Saturday and Sunday. Thus, he cycled 24 kilometers more on Saturday than on Sunday. - Languages 7160
Out of 100 students, 30 studied German, 28 studied German, 42 learned French, eight studied German and German, 10 German and German, and 5 German and German. How many students have learned all three languages? - Filip's 7158
Filip's friend is three times younger than Filip's father. He will be two years younger. How old is Filip's friend? - The sales
The sales tax rate is 4.447% for the city and 4% for the state. Find the total amount paid for two boxes of chocolates at $17.96 each. - Number 7148
Find a number that is 14% as much as 5% of 196 - Soldier
An experienced soldier digs a good trench in 30 hours. Two soldiers dug the same trench every 40 hours. How many hours will the ditch dig all three together? - Circumference 7143
Peter drew a regular hexagon, the vertices of which lay on a circle 16 cm long. Then, for each vertex of this hexagon, he drew a circle centered on that vertex that ran through its two adjacent vertices. The unit was created as in the picture. Find the ci - Mathematical 7136
Out of 50 pupils, 44 solved at least one of the Olympiads - MO Mathematical Olympiad and BO Biology Olympiad. Twenty pupils still need to solve the MO. Of those who dealt with both Olympiads, 1/3 of those who dealt with just one were. How many pupils solv - Enrolled: 7135
In day mode, Jirka enrolled: sleep 50%, learning 25% free time (fun + help at home) 25%. How many hours a day does he spend on each activity? - Bedrich and Adam
When Bedrich is as old as Adam today, Adam will be 14 years old. When Adam was as old as Bedrich, Bedrich was two years old today. How old are Adam and Bedrich today? - MO Z8-I-1 2018
Fero and David meet daily in the elevator. One morning, they found that if they multiply their current age, they get 238. If they did the same after four years, this product would be 378. Determine the sum of the current ages of Fero and David. - Prime number
Jan wrote any number from 1 to 20. What is the probability that he wrote the prime number? - Percentage 7129
The shop reduced the original price of the skis by 20% in January. They reduced the new price by another 20% at the beginning of February. By what percentage was the price of the skis lower than the original price? - Exercisers
How many exercisers are in the gym (minimum number) if there is one left after ordering into three, four, and five steps? - Reservoir 3
How many cubic feet of water is stored in the reservoir that has a length of 200 feet, a width of 100 feet, an overflow depth of 32 feet, and a current water level of 24 feet?
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