Examples for secondary school students - page 93 of 232

Number of problems found: 4622

Lifespan
The lifetime of a light bulb is a random variable with a normal distribution of x = 300 hours, σ = 35 hours. a) What is the probability that a randomly selected light bulb will have a lifespan of more than 320 hours? b) To what value of L hours can the la
Slow saving in banks
How long will it take to save € 9,000 by depositing € 200 at the beginning of each year at 2% interest?
Percentage increase
What is the annual percentage increase in the city when the population has tripled in 20 years?
Component failure probability
The daily product consists of 1000 components, and the probability of failure of any component during the use of the device is 0.001. It does not depend on other components. What is the probability of failure of two components in the investigated period o
Magnified cube
If the lengths of the cube's edges are extended by 5 cm, its volume will increase by 485 cm³. Determine the surface of both the original and the magnified cube.
Sapling planting calculation
During the afforestation, 2,950 saplings were planted in three days. On the second day, 25% more saplings were planted than on the first day, and on the third day, 15% more than on the second day. How many saplings were planted on each day?
Number sum calculation
Of the four numbers, the second is five larger than the first, the third two smaller than the first, and the fourth is twice larger than the first. Find these numbers if their sum is 38.
Internal angles
In the ABC triangle, the magnitude of the inner angle beta is one-third the magnitude of the angle alpha and 20° larger than the magnitude of the gamma angle. Determine the magnitudes of the interior angles of this triangle.
Caramel sharing calculation
Anička and Jana shared 21 caramels, while Jana had 40% of what Anička received. How many caramels did she get?
Viewing angle
The observer sees a straight fence 60 m long at a viewing angle of 30°. It is 102 m away from one end of the enclosure. How far is the observer from the other end of the enclosure?
Reception nationality distribution
Forty-eight people were present at the reception. Among them were Czechs, Slovaks, and Germans. Slovaks were 4 more than Czechs and Germans 6 less than half Czechs and Slovaks. How many Czechs, Slovaks, and Germans were there at the reception?
Worker reward distribution
Three employees received a reward of CZK 5,000 for the improvement proposal. They divided the money according to work so that the first got twice as much as the second, and the second got three times as much as the third. How many crowns did each person r
Adam
Adam has half more money in his right pocket than in his left pocket. If he transferred 40 crowns from the left pocket to the right, he would have the same in both pockets. Calculate how many crowns Adam has in his left pocket more than in his right. How
Triangle from median
Calculate the perimeter, area, and magnitudes of the triangle ABC's remaining angles: a = 8.4; β = 105° 35 '; and median ta = 12.5.
All use computer
It is reported that 72% of working women use computers at work. Choose three women at random, and find the probability that all three women use a computer in their jobs.
Quiz or test
I have a quiz with 20 questions. Each question has four multiple-choice answers, A, B, C, D. THERE IS NO WAY TO KNOW THE CORRECT ANSWER OF ANY GIVEN QUESTION, but the answers are static, in that if the "correct" answer to ; 1 = C, then it will always be e
The modulus
Find the modulus of the complex number 2 + 5i
The half life
The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. Starting with 145 grams of a radioactive isotope, how much will be left after three half-lives?
Average height
There are twice as many girls in the class as there are boys. The average height of girls is 177 cm, and boys 186 cm. What is the average height of students in this class?
Class girl percentage
In the 7A class, the ratio of boys to girls is 2:3. What percentage of the class are girls?

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