Question 1024476
Assuming the weights of the five questions are equal, the student has to get 4 or 5 correct answers.

==> probability of passing by guessing is p(4) +p(5) = {{{C(5,4)*0.75^1*0.25^4 +
C(5,4)*0.75^0*0.25^5 = 1/64}}}, or 1.5625%