Math practice for 13 year olds - page 56 of 351
Number of problems found: 7015
- Times 81462
5 to -11 times 5 to -7/5 to zero times 5 to -15 minus ( -5 ) to -2
- Intersection 81457
Two cars started from the right-angled intersection of two roads. The first at a speed of 80 km/h and the second at a speed of 60 km/h. How fast are they moving away from each other?
- Neighbor 81456
Mr. Novak earns as many euros in half a year as his neighbor in 4 months. The neighbor earns 420 euros more per month than Mr. Novak. What is the monthly income of Mr. Novak?
- Arithmetic 81453
A set of numbers 5,8,13,15,17,19 is given. What number should be added so that the arithmetic mean is 16?
- Probability 81446
What is the probability that each digit is different in a five-digit number?
- Received 81440
At the flower festival, young growers sold cactus plants for CZK 12 and indoor violet plants for CZK 9. They sold a total of 47 pieces of flowers of both types and received CZK 501. How many cacti and how many violets did they sell?
- Evaporating 81430
Sea water contains 3.4% salt. How much salt do we get by evaporating 25 kg of seawater, and how much water evaporates?
- Produced 81413
A cube of sugar weighs 6 grams. How many sugar cubes are produced from one sugar beet that weighs 0.9 kg; if its sugar content is 18 percent?
- Kilometers 81410
The tourist walked 1/4 of the way at a speed of 4.5 km/h, 2/5 at a speed of 4 km/h, and the remaining 7 km at a speed of 5 km/h. How many kilometers did he run, and how long did the journey take him? Calculate the time in a fraction.
- Calculate 81406
Calculate the equation and do the test. (x+6)/2 - (x+4)/4 = (2x+1)/3 – (x-4)/6
- Started 81404
At 7:30 AM, the bus left at a speed of 45 km/h, and at 8:00, a car behind it started at 65 km/h. Where and when did they meet?
- Calculation 81402
In an isosceles triangle, the side a=b= 21 cm, and the triangle's height is 19 cm. Find out the base and perimeter of the triangle (sketch, calculation, answer).
- Calculation 81401
A regular four-sided pyramid has a volume of 2,160 liters and a base edge length of 12 dm. Calculate the height of the needle (sketch, calculation, answer).
- Probability 81395
What is the probability that heads come up 5 times a row when tossing a coin? Write the result as a fraction.
- Gradient of the railway
Calculate the gradient of the railway line, which has an elevation of 22.5 meters in a section of 1.5 kilometers. For railways, the result is given in h (per mille).
- Quadrilateral 81385
A regular quadrilateral pyramid with base edge length a = 15cm and height v = 21cm is given. We draw two planes parallel to the base, dividing the height of the pyramid into three equal parts. Calculate the ratio of the volumes of the 3 bodies created.
- Minutes 81382
The water barrel filled to 2/3 of its volume in 42 minutes. How long will it take to fill the barrel?
- Friends 81380
In the lottery, where 326 numbers are drawn, Maros marked 7 numbers on the ticket. Kamil marked 11 numbers in another lottery, and 421 numbers were drawn. Which of these friends has a better chance of winning?
- Maximilian 81372
Tadeas the beetle set off from the house towards the cabbage leaf at a 20 m/min speed. Two minutes later, the Maximilian beetle followed him at 24 m/min speed. They both came to the cabbage leaf at the same time. How far was the letter from their house?
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