What is the probability of passing a 10-item multiple choice quiz, if there are 4 choices, A to D for every question, and if the passing mark is 8/10, assuming that you guessed the answers to all the questions?

Answer 1

prob(right) = 1/4
prob(wrong) = 3/4

if passing grade is 8/10, then I will pass if I get
8/10 or 9/10 or 10/10
prob of that
= C(10,8)(1/4)^8 (3/4)^2 + C(10,9)(1/4)^9 (3/4) + (1/4)^10
= appr .00041

check my arithmetic

Answer 2

So what are the answers? Im stuck as well

Answer 3

Could somebody help me lol