Answer:
9.72405%
Step-by-step explanation:
Binomial Probability
(N choose k) p^k (1-p)^(n-k)
N=7 seeds planted
p= 100% - 70% = 30% = 0.3 <--- we are interested in the plant NOT growing
(1-p) = 70% = 0.7 <--- 70% chance the plant will survive and grow
k=4 <--- we want four of them to fail
The probability is:
(7 choose 4) * (0.3)^4 (0.7)^3 =
7!/(4!3!) (0.3)^4 (0.7)^3 =
(7*6*5/3*2) (0.3)^4 (0.7)^3 =
7*5 (0.3)^4 (0.7)^3 =
35 * 0.0081 * 0.343 = 0.0972405 = 9.72405%
