Collect All The ToysDiscrete Mathematics Level 3
Each sealed Storelings pack contains a single Storeling toy chosen at random. There are 3 distinct Storelings toys in the set, and each toy has an equal chance to be in each pack. Also, each pack is independent of every other pack.
What is the expected value of the number of packs one would need to open in order to obtain at least one copy of each toy?