Avocado seed probability

The probability of sprouting each avocado pit is 0.9. We planted 3 stones.
What is the probability that exactly two of them will sprout?

Final Answer:

p₂ =  0.243

Step-by-step explanation:

$$\begin{gathered} p=0.9 \\ n=3 \\ {p}_2=\left(\genfrac{}{}{0ex}{}{n}{2}\right)\cdot p^2\cdot (1-p{)}^{n-2}=(\genfrac{}{}{0ex}{}{3}{2})\cdot 0.9^2\cdot (1-0.9{)}^{3-2}=3\cdot 0.9^2\cdot 0.1^1=0.243 \end{gathered}$$

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