John stands in front of a sugary soft‐drink vending machine.

Question

John stands in front of a sugary soft‐drink vending machine. This machine randomly

dispenses one of four different flavored colas. The machine contains exactly two cans of each

flavor. Find the p.m.f. for the number of times John must press the button before he receives

at least one soda of each flavor.

Answer 1

I’m not sure what p.m.f stands for. The answer to the maximum number of times he must press the button to get one can of each flavor is 7 . That is because you could conceivably get 2 of all three flavors without getting a can of the fourth. But then all that would be left would be the fourth flavor, so on the seventh try you would have to get the fourth flavor