Question 1018826
It is the probability of answering 4 questions, 5 questions or 6 questions correctly.
probability of 4 is 6C4(0.75)^2(0.25)^4
probability of 5 is +(0.75)(0.25)^5
probability of 6 is 0.25^6=
0.0330+0.004+0.0002=0.0334