math help please!!! *prob. distribution*?
A box contains 25 marbles, 30% of which are green. A contestant reaches in the box to choose three marbles; the contestant will win $200 if he or she selects a green marble, but will lose $120 for any other colour. If the marble is not replaced each time, is this a fair game? Explain.
- nbsaleLv 61 month ago
You should grade the person who wrote the question "F", since you can't have 7.5 green marbles.
Also, the rest of the question is poorly worded. Does he get 200 for EACH green marble, or only if there is at least one? I'll assume the latter Does he lose 120 for EACH marble not green, or only if ALL are not green? Again, I'll assume the latter
Let's assume there are 7 green.
There is 1 way to get 3 green
There is 18(7C2) ways to get 2 green
There is 7(18C2) get 1 green
Add those up and multiply by 200. Call that A.
There is 18C3 ways to get 0 green.
Multiply that by 120. Call that B
If A=B the game is fair
If A>B, the game is in the player's favor.
If A<B, the game is "rigged" against the player.
- davidLv 71 month ago
Your question makes no sense. 30% of 25 is 7.5 marbles... half of a marble is green??