Maths practice for 14 year olds - page 141 of 362

Number of problems found: 7228

Student exam probability
There are 28 students in the IK3 class. Three pupils will be examined. Nineteen pupils are ready for the exam. What is the probability that all three will be unprepared?
Cheetah antelope pursuit
The antelope was 100 m away from the cheetah. The moment the cheetah started running, antelope took off running. The cheetah ran at an average speed of 1200 m per minute, and the antelope 700 m per min. In how many seconds was the cheetah able to catch up
Target miss probability
The target is divided into three zones. The shooter's probability of hitting the first zone is 0.18, the second zone is 0.22, and the third zone is 0.44. What is the likelihood that he will miss the target?
Cube edge
Calculate the size of the cube edge if the diagonal of the wall is 8 cm.
The encore
The rock band had a 15-minute encore at their concert, which accounted for 12% of the total length of the concert. What was the total length of the concert?
The price
The calculator's price gradually decreased from 65 euros to 30 euros, then to 10 euros, and finally to 4 euros. What percentage were the individual reductions? What percentage of the original price was reduced?
Cauliflower sales
Miss Cabbage sells vegetables in the market. Yesterday, she offered two types of cauliflower - a large one for 25 CZK and a small one for 15 CZK. In the morning, she sold 8 boxes of 20 heads of cauliflower and thus earned 3,270 CZK. How many large and how
Worker repair time
The worker performs the repair work in 20 days, and his assistant does the job himself in 60 days. How many days would they work together?
Reservoir pump filling
The reservoir is filled with a large pump in 20 hours, a medium in 24 hours, and a small one in 30 hours. If all pumps are switched on simultaneously, how many hours will it be filled?
Atmospheric pressure
The area of the horizontal plate is 0.80 m². The atmospheric pressure around the plate is 1100 hPa. 1. How much pressure does the air exert on the plate from above? 2. What is its direction? 3. Is the magnitude of this force different if the plate is tilt
Coffee
One kilogram of cheaper coffee costs CZK 150, and one kilogram of more expensive coffee costs CZK 200. We have to prepare a mixture of 35 kg of coffee for 180 CZK. How do we prepare the mixture (how many of which kind of coffee do we need)?
Candy mixture
In a luxury praline factory, they prepared 3.2 kg of a mixture of two types of candies for CZK 273 per 1 kg. Marzipan candies cost 345 CZK/kg and nougat 255 CZK/kg. How many kilograms of each type of candy were used?
The sum
The sum of the squares of two immediately following natural numbers is 1201. Find these numbers.
Balloon buoyancy force
The balloon filled with hot air has a volume of 1440 m³. How large a buoyancy force acted on the balloon in the air with a density of 1.3 kg/m³?
Pharmacist
The pharmacist had a 12 liter vessel of herbal lotion, which contained a 30% active ingredient. Her assistant poured 18 liters of herbal lotion, containing 45% of the active ingredient, into a container. What percentage of herbal lotion was produced?
Triangle angle
For the interior angles of a triangle, the angle β is twice as large, and the angle γ is three times larger than the angle α. Is this triangle right?
The bun
The bun costs CZK 2, and the rolls CZK 3.5. Hannah bought 22 pieces of bread, bought only buns and rolls, and paid CZK 65. how many rolls did she buy, and how many rolls?
Muesli
You want to mix your own muesli on a specialized website. 200 g of muesli base costs 170 CZK. You want to add cornflakes in chocolate to the basics. 50 g of this ingredient costs 13 CZK. How much do you pay for a 150 g mixture when both components weigh t
Balloon flight
From the pilgrimage, Nicole has a balloon on a two-meter-long string, the end of which is held 60 cm above the ground. The balloon floats diagonally from Nicole and is 145 cm horizontally away from her. How high is the balloon from the ground?
Concert ticket
Noah wants to save $60 to purchase a concert ticket. If he has saved $45 so far, what percentage of his goal has he saved? What percentage remains?

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