Question

В 8-м классе учится менее 50 школьников. За контрольную работу 1/7 учеников получили пятёрки, 1/3 – четвёрки, 1/2 – тройки. Сколько работ оказалось неудовлетворительных?

Answer 1

1/2 - тройки, значит остальные 1/2 5,4 и 2. Значит 1/2-1/7-1/3=(21-6-14)/42=1/42.

Всего в классе 42 ученика; 5 у 6, 4 у 14, тройки у 21 и 2 у 1.

Ответ: неудовлетворительная оценка у одного ученика

 

Answer 2

Calculating Unsatisfactory Grades

To calculate the number of unsatisfactory grades, we can use the given fractions of students who received different grades for the test.

Given: - Total number of students in the 8th grade: less than 50 - Fraction of students who received A's (5): 1/7 - Fraction of students who received B's (4): 1/3 - Fraction of students who received C's (3): 1/2

Let's calculate the number of unsatisfactory grades.

Solution:

1. Calculate the number of students who received each grade: - Number of students who received A's (5): $\frac{1}{7} \times \text{Total students}$ - Number of students who received B's (4): $\frac{1}{3} \times \text{Total students}$ - Number of students who received C's (3): $\frac{1}{2} \times \text{Total students}$

2. Calculate the number of unsatisfactory grades: - Unsatisfactory grades = Total students - (A's + B's + C's)

Let's calculate the number of unsatisfactory grades using the given fractions and the total number of students.

Calculation:

1. Number of students who received A's (5): $\frac{1}{7} \times 50 = 7.14 \approx 7$ 2. Number of students who received B's (4): $\frac{1}{3} \times 50 = 16.67 \approx 17$ 3. Number of students who received C's (3): $\frac{1}{2} \times 50 = 25$

Unsatisfactory Grades:

Unsatisfactory grades = Total students - (A's + B's + C's) Unsatisfactory grades = 50 - (7 + 17 + 25) Unsatisfactory grades = 50 - 49 Unsatisfactory grades: 1

Therefore, the number of works that turned out to be unsatisfactory is 1.