Five different CD-Rom games: garble, trapster,zoom, bungie, and blast'em are offered as a promotion by SugrRush cereals. One game is randomly included ith each box of cereal.
Determine the probability of getting all 5 games if 12 boxes are purcahsed.
4 answers
I get an answer of 0.678002688, but I don't have time to explain why.
The formula The Wizard used was
1 - 5*(4/5)^12 + 10*(3/5)^12 - 10*(2/5)^12 + 5*(1/5)^12.
See if you can understand the logic. The (4/5)^12 term is the probability that one of the five types is missing. The remaining terms take into account the probability that two, three or four types are missing. There are ten ways of choosing the two or three that may be missing, but only five ways of choosing the one or four types that may be missing.
1 - 5*(4/5)^12 + 10*(3/5)^12 - 10*(2/5)^12 + 5*(1/5)^12.
See if you can understand the logic. The (4/5)^12 term is the probability that one of the five types is missing. The remaining terms take into account the probability that two, three or four types are missing. There are ten ways of choosing the two or three that may be missing, but only five ways of choosing the one or four types that may be missing.
The answer of The Wizard of Odds is correct. For an explanation of how it was arrived at, see the "Roulette board (0,00)" question at
http://wizardofodds.com/askthewizard/197
The same method was used.
http://wizardofodds.com/askthewizard/197
The same method was used.
why don't you explain??!!!???
1 answer