This question isn't in a book, but I want to know the answer for myself.
Q. If I take an MCQ test with 40 questions, each question has 4 possible answers with only one being correct, what is the probability of getting 40/40 in the test by guessing?
I've tried solving this by doing (1/4)^40, but then I thought of doing 1/(160C40) and I got different answers. Why is that so and which is the correct way.
Q. If I am sure of 30 questions and unsure about 10 (have to guess them), what is the probability of getting above 30 in the test.(I don't lose marks for wrong answers)