A test consists of 10 multiple choice questions, each with 5 possible answers, one of which is correct. To pass the test a student must get 60% or better on the test. If a student randomly guesses, what is the probability that the student will pass the test?

Question

anonymous · Answer

six or more right
probability you get any one right is $\frac{1}{5}=.2$ use the binomial 
$$P(X=6)=\binom{10}{6}.2^6\times .8^4$$
$$P(X=7)=\binom{10}{7}.2^7.8^3$$
$$P(X=8)=\binom{10}{8}.2^8\times .8^2$$
$$P(X=9)=\binom{10}{9}.2^8\times .8$$
$$P(X=10)=.2^{10}$$
compute and add

anonymous · Answer

here is the first one http://www.wolframalpha.com/input/?i=%2810+choose+6%29.2^6*.8^2

anonymous · Answer

I dont understand where the 8^? came from