This is an example from the text I'm using but I just want to make sure that I'm not going crazy here.
A multiple choice exam consists of 25 questions each with five choices with once choice is correct. Randomly select an answer for each question. Let X be the random variable representing the total number of correctly answered questions.
(c) Find the expected value of the number of correct answers.
a and b are inconsequential, my issue is with (c).
The expected value is just $n*p$ is it not? The answer in the book says it is $(25)(0.2)(.8)$ but that makes absolutely no sense to me as that is the variance, not the expected value.