What is the expected number of mutant flies that must be inspected to find the first one with purple eyes? What is the expected number of purple-eyed flies that will be found if this many are checked? What is the probability that exactly one purple-eyed fly is found if this many are checked?
A lab is screening to find mutant flies. 10% of the offspring of mutant flies have purple eyes, while none of the offspring of wild type flies have purple eyes. Suppose that purple-eyed flies are just as easy to catch as ordinary flies.