Student Request : English Formula showing each step and if binomial applies please use calculator TI-83.

11.There are 50 questions on a multiple choice exam. For each there are 5 choices, only one is correct. If you need to get at least 30 questions correct to pass the test, what is the probability of passing this test by making random guesses?

12.Referring to the previous problem, find the mean (expected value) and variance for the number of questions you answer correctly by making random guess.