Answer:
19%
Step-by-step explanation:
First, let's notice that having 1 or more rotten oranges in the sample is the complement of having 0 rotten oranges in the sample. That means
proba (1 or more rotten oranges) + proba (0 rotten oranges) = 100%
We will focus in the case of 0 rotten oranges that's easier and then we go back to this last equation.
For 0 rotten oranges, we need that the customer picks 3 good oranges. As there are 4 rotten oranges in the crate of 60, we have [tex]60-4=56[/tex] good oranges.
So, the customer has a 56/60 chance of getting a good orange. As he needs 3 good oranges at the same time, he has [tex]\frac{56}{60} *\frac{55}{59} *\frac{54}{60}= \frac{1386}{1711}[/tex] chance.
Therefore, proba(0 rotten oranges) = [tex]\frac{1386}{1711}[/tex] = 81% (approximately)
Going back to the first paragraph, we have proba(1 or more rotten oranges) = 100% - proba(0 rotten oranges) = 100% - 81% = 19%
