Question

Учащиеся младших классов составляют 45% всех учащихся школы. Учащихся с 5 по 9 классы 130% больше, чем 10-11 классов. Сколько в школе старшеклассников, если в ней учится 1500 человек? С полным решением :)

Answer 1

Процент - это сотая часть числа, значит, 45% = 0,45;  130% = 1,3

1) 1500 * 0,45 = 675 учащихся обучаются в младших классах

2) 1500 - 675 = 825 учащихся с 5 по 11 классы (теперь это у нас 100%)

10 - 11 классы - х учащихся;   5 - 9 классы - х + 1,3х - на 130% больше

х + х + 1,3х = 825

3,3х = 825

х = 825 : 3,3 = 250 учащихся в 10 - 11 классах

825 - 250 = 575 учащихся в 5 - 9 классах

Проверка: 250 + 250 + 1,3 * 250 = 500 + 325 = 825 учащихся - верно.

Ответ: в школе 250 старшеклассников.

Answer 2

Given Information:

- 45% of all students in the school are in the lower grades. - The number of students in grades 5 to 9 is 130% more than the number of students in grades 10 and 11. - The total number of students in the school is 1500.

Calculation:

Let's assume the number of students in grades 10 and 11 is x.

According to the given information, the number of students in grades 5 to 9 is 130% more than the number of students in grades 10 and 11. This can be expressed as:

Number of students in grades 5 to 9 = x + 1.3x = 2.3x

We also know that 45% of all students in the school are in the lower grades. This can be expressed as:

Number of students in lower grades = 0.45 * Total number of students

Since the total number of students in the school is 1500, we can calculate the number of students in the lower grades:

Number of students in lower grades = 0.45 * 1500 = 675

Now, we can set up an equation to find the value of x:

Number of students in grades 5 to 9 + Number of students in grades 10 and 11 = Total number of students

2.3x + x = 1500

Simplifying the equation:

3.3x = 1500

x = 1500 / 3.3

x ≈ 454.55

Since we can't have a fraction of a student, we can round down the value of x to the nearest whole number:

x = 454

Therefore, the number of students in grades 10 and 11 is approximately 454.

To find the number of students in grades 5 to 9, we can substitute the value of x into the equation:

Number of students in grades 5 to 9 = 2.3 * 454 ≈ 1044.2

Since we can't have a fraction of a student, we can round down the value of the number of students in grades 5 to 9 to the nearest whole number:

Number of students in grades 5 to 9 ≈ 1044

To find the number of senior students (grades 10 and 11), we can subtract the number of students in grades 5 to 9 from the total number of students:

Number of senior students = Total number of students - Number of students in grades 5 to 9

Number of senior students = 1500 - 1044 = 456

Therefore, there are approximately 456 senior students in the school.

Answer:

If there are 1500 students in the school, there are approximately 456 senior students (grades 10 and 11).