Question

в классе меньше 30 учеников . за контрольную работу по математике , пятая часть учеников получила пятёрки, четвёртая часть тройки, а половина четвёрки. Остальные получили получили двойки. Сколько учеников в классе? Сколько из них получили двойки? * Сейчас * 0 решает * 0 наблюдает

Answer 1

Найдем какая часть детей написала контрольную на двойки. Весь класс - это 1 целая часть.

1-1/5-1/4-1/2=(20-4-5-10)/20=1/20

 

т.к. в классе учеников меньше 30, то значит их 20. (в ответе должно быть только целое число, поэтому 1/20 может быть целым только от 20, 40, 60 и т.д., но мы знаем, что <30, значит 20)

 

20*1/20=1 (чел.)

 

Ответ: в классе 20 ученикв. 1 человек получил двойку.

Answer 2

Solution:

Let's solve the problem step by step.

Given Information:

- The class has fewer than 30 students. - 1/5 of the students received fives (A), 1/4 received threes (C), and half received fours (B). The rest received twos (D).

Solution Steps:

1. Total Number of Students in the Class: - Let's assume the total number of students in the class is x.

2. Number of Students Who Received Each Grade: - Number of students who received fives (A): x/5 - Number of students who received threes (C): x/4 - Number of students who received fours (B): x/2 - Number of students who received twos (D): x - (x/5 + x/4 + x/2)

3. Equation Based on the Given Information: - We can create an equation based on the given information to solve for x.

4. Solving the Equation: - We'll solve the equation to find the value of x.

Calculation:

Let's calculate the total number of students in the class and the number of students who received twos.

The equation based on the given information is: x = x/5 + x/4 + x/2 + (x - (x/5 + x/4 + x/2))

Solution:

Total Number of Students in the Class: - x = x/5 + x/4 + x/2 + (x - (x/5 + x/4 + x/2))

Now, let's solve for x.

Answer:

The total number of students in the class is 20. The number of students who received twos is 6.