how many students are good in mathematics only and how many students are not good in any of the three courses
1 answer:
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<h2>The required "option c) 4.3" is correct.</h2>
Step-by-step explanation:
Given,
Total number of multiple choice questions = 17
To find, the mean for the number of correct answers = ?
Each question has four possible answers.
If guessing at random:
There is only one in four chances.
= 25 % chance of getting a particular question right.
This is the same probability for each of the 17 questions.
If there is a 25 % chance of getting any given question right.
There are 17 questions.
∴ The total number of questions you will expect to get right =
25 % × 17
=
=
= 4.25
≈ 4.3
∴ The mean for the number of correct answers = 4.3
Thus, the required "option c) 4.3" is correct.