What is the probability a box does not contain a rotten apple?

Question

Apples has 0.2 chance of being rotten. The apples are then packaged randomly into boxes containing 5 apples each.

Clean boxes are defined as boxes without a single rotten apple.

What is the expected value of clean boxes ratio to total boxes? i.e. clean boxes/total boxes

edit 1: Toby requested clarity regarding how it's packaged.

edit 2: removed background information, it's not informative.

Answer 1

The probability of a fresh apple is $\frac 45$.
So the probability of a clean box is $(\frac 45)^5 = \frac {1024}{3125}.$
So the ratio of clean to total boxes is $1024 : 3125$.