Question 308188
Let c=correct answers and w=wrong answers
c=.25 and w=.75 for each question.
Expand: (c+w)^10
For 6 correct the coefficient is nCr=10C6=210
210c^6w^4
=210*.25^6*.75^4
=.0162 Probability of exactly 6 correct guesses on a 10 question multiple choice test.
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Ed