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rembrendgirly
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If a seed is planted, it has a 80% chance of growing into a healthy plant. if 9 seeds are planted, what is the probability that exactly 4 don't grow?

Verified Answer :

toporc

The probability of a seed not growing into a healthy plant is 1 - 0.8 = 0.2.
\(P(4\ seeds\ don't\ grow)=9C4\times0.2^{4}\times0.8^{5}=0.066\)
The answer is the probability = 0.66 or 6.6%

mrinconj

This is a binomial probability because the plant can grow healthy or not. You should apply binomial probability formula when x = 4, n = 9, p = 0.2 (because one wants to know the chance of no growth).
P(x=4)= 9C40.2^40.8^(9-4) = 9!/(4!(9-4)!)0.2^40.8^5 =1260.2^40.8^5=0.066 = 6.6%