Probability
posted by Student on .
Thank you for the explanation MathMate! Would the answer to this question be A?
Darby guesses the answers to six questions on the math portion of her college entrance exam. Each question is a true or false question. What is the approximate probability that at least 4 of her answers are correct?
A. 0.23
B. 0.34
C. 0.66
D. 0.78

Sorry that the previous response was for 4 correct.
The number ways to have at least 4 correct is
(6,4)+(6,5)+(6,6)
=15+6+1
=22
To total number of ways to respond is
2^6=64
So the probability is 22/64. 
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