Answer: Approximately 0.385802
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Step-by-step explanation:
The expression we'll type into the calculator is
4*(5/6)^3*(1/6)^1
The (5/6)^3 portion is the idea of him making 3 free throws. Each free throw is assumed to be independent of any others. In reality, there is likely some dependency however, but we'll assume independence for the sake of simplicity.
The (1/6)^1 portion is the probability of missing a certain free throw.
The 4 out front is because there are 4 possible free throws he could miss
A = made a free throw
B = missed a free throw
The four combos are
AAAB
AABA
ABAA
BAAA
For example, the notation AABA means "he made the first two, missed the third, and made the fourth shot". So this is why we have the 4 out front.
For more information, check out the binomial probability distribution.
Computing the expression mentioned, we get 4*(5/6)^3*(1/6)^1 = 0.385802 which is approximate.