Question

18% учеников сдавших экзамен по математике, не смогли решить ни одну задачу. 120 учеников решили задачи с ошибками. Отношение числа учеников, решивших все задачи, на число, не решивших ни одной задачи 7:3. найдите число учеников, не решивших ни одной задачи. Помогите пожалуйста.​

Answer 1

Ответ:

Пошаговое объяснение:

Составим пропорцию

проценты    часть

18                   3

x                    7

7*18/3=x

x=42

значит, 120 учеников - 30%

             x учеников     - 100%

всего 400 учеников

400*18/100=18*4=72 ученика не решили ни одной задачи

Answer 2

Calculation of the Number of Students Who Couldn't Solve Any Problems

To find the number of students who couldn't solve any problems, we need to use the given information about the ratio of students who solved all the problems to those who couldn't solve any.

Let's assume the number of students who couldn't solve any problem is x. According to the given information, the ratio of students who solved all the problems to those who couldn't solve any is 7:3.

Therefore, we can set up the following equation:

7x = 3(120)

Simplifying the equation, we have:

7x = 360

Dividing both sides of the equation by 7, we get:

x = 360 / 7

Using a calculator, we find that x ≈ 51.43.

Since the number of students must be a whole number, we can round up to the nearest whole number. Therefore, the number of students who couldn't solve any problem is approximately 52.

Please note that this calculation assumes that the given ratio is accurate and that there are no other factors affecting the number of students who couldn't solve any problems.