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I need help with a probablity question.?
If there are three bags that each contain 7 red marbles and 13 blue marbles, what is the chance I will grab at least one red marble, if I grab one marble from each of the bags?
3 Answers
- 5 years agoFavorite Answer
You have a 65% chance of pulling a blue marble from each bag. The chances of pulling 3 blue marbles is:
(13/20) * (13/20) * (13/20)
The chances of pulling a red marble would therefore be:
1 - (13/20)^3
1 - 2197/8000
(8000 - 2197) / 8000
5803/8000
0.725375
You have a roughly 72.5% chance of pulling at least one red marble
- 5 years ago
13/20 chance for blue on each go
(13/20)^3 = chance of getting 3 blue marbles, therefore the same as getting no red marbles
1 - (13/20)^3 = chance of getting atleast 1 red marble
1 - (13/20)^3 = 0.725375
- Iggy RockoLv 75 years ago
p(at least one red marble) =
1 - p(all blue marbles) =
1 - (13/20)^3 =
1 - 2197/8000 =
5803/8000
