<PRE><B>Question 1079029</B>
Consider two applications of the binomial probability distribution
:
Probability(k successes out of n trials) = nCk * p^k * (1-p)^(n-k)
:
nCk is (n! / (k! * (n-k)!)
:
For this problem p is 0.5 and n is 3 or 4
:
P(exactly 2 girls in 3 or 4 children) = P(2 girls out of 3 children) + P(2 girls out of 4 children) = 0.375 + 0.375 = 0.75
:
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