If a seed is planted, it has a 60% chance of growing into a healthy plant.

Question

If 6 seeds are planted, what is the probability that exactly 4 don't grow?

Answer 1

Here, let's define "success" to be that the plant doesn't grow. This would be 1 - .6 = .4.

We construct a binomial distributions with 6 trials (6 seeds planted). We want 4 events.

B(6, .4)
P(X = 4) = .138

Answer 2

6C4 .4^4 .6^2 = 0.138