Survival Probability Of The 6th Fly that Attempt To Pass A Spider

A spider eats three flies a day. Until he fills his quota, he has an even chance of catching any fly that attempts to pass. A fly is about to make the attempt. What are the chances of survival, given that five flies have already made the attempt today?

A.   1/2 C.   3/4
B.   1/4 D.   2/3


Answer Key