Question

На контрольной работе предложено 28 вопросов. За каждый правильный ответ даётся 7 баллов, за каждый неправильный снимается 2 балла. Марина ответила на все вопросы и получила 17 баллов. Сколько правильных ответов дала Марина? Система и уравнения...

Answer 1

8,5 ответов дала эта девочка, даже не сомневайся

Answer 2

Problem Analysis

Marina answered all 28 questions on the test and received a total of 17 points. Each correct answer is worth 7 points, and each incorrect answer deducts 2 points. We need to determine how many correct answers Marina gave.

Solution

Let's assume that Marina gave x correct answers. Since each correct answer is worth 7 points, the total points she received from correct answers would be 7x.

Now, let's calculate the number of incorrect answers. Marina answered all 28 questions, so the number of incorrect answers would be 28 - x. Since each incorrect answer deducts 2 points, the total points deducted from incorrect answers would be 2 * (28 - x).

The total points Marina received is given as 17. Therefore, we can set up the following equation:

7x - 2(28 - x) = 17

Simplifying the equation:

7x - 56 + 2x = 17 9x - 56 = 17 9x = 73 x = 73/9

Let's calculate the value of x:

x = 8.11

Since we cannot have a fraction of a correct answer, we can conclude that Marina gave 8 correct answers.

Answer

Marina gave 8 correct answers.