Question 972399: Suppose that a student selects all his answers to this test entirely at random among choices (A) through (E), never choosing (F). If indeed, "none of these" is not the correct answer to any of the questions, and the correct answers are positioned entirely at random, what is the expected score for this student? Recall this test consists of 25 problems and each problem is worth 4 points.
I know that (F) is considered "none of these."
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Then F is a red herring. It is not a correct answer, and the student never chooses it.
Therefore, the expected number of questions answered is the probability of guessing right from 5 choices multiplied by the number of questions.
That is 25 * (1/5)=5
His score would be a 20.
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