SOLUTION: A student takes a multiple choice test with 10 questions (four answers per question) and guesses at each of the ten. The probability that he gets at least half right?

Question 346633: A student takes a multiple choice test with 10 questions (four answers per question) and guesses at each of the ten. The probability that he gets at least half right?
Answer by edjones(8007) (Show Source): You can put this solution on YOUR website!
Expand the binomial (a+b)^10 Let a=.75 and b=.25
a^10=.0563 all wrong
10a^9b=.1877
45a^8b^2=.2816
120a^7b^3=.2503
210a^6b^4=.1460 six wrong
==========>.9219
.
1-.9219=.0781 The probability that he gets at least half right.
.
Ed
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