Posted by Hannah on Wednesday, April 13, 2011 at 5:37pm.
In total, there are 25+28+38=91 jelly beans.
Using (n,r) to stand for "n choose r"
To choose y yellow, g green and r red jelly beans, the number of ways to choose is given by
and the number of ways to choose the same number of jelly beans irrespective of colour is
So the probability is:
(25,y)*(28,g)*(38,r) / (91,y+g+r)
For 5 yellow, we not worry about the other two colours, so they can be combined, call it x. We need 8 of x.
For (b), it is a similar expression. I get approx. 0.0012
For (c), you would choose 13 out of green and red, and subtract from the probability of 1.
See also following link for a detailed explanation:
statistics - Four jelly beans are selected, one at a time from a bowl containing...
math - danielle has 30 jelly beans and 18 green jelly beans. What is the ratio ...
Math - A box has 8 blue and 5 green jelly beans. A bag has 6 blue and 8 green ...
math - The ratio of red jelly beans to yellow jelly beans in a dish is 2:3. If I...
math - Results of a survey of fifty students indicate that 30 like red jelly ...
math - one bag of jelly beans contains 14 red jelly beans. how many red jelly ...
Math - The ratio of red jelly beans to yellow jelly beans in a dish is 3:4. If ...
Math - The ratio of red jelly beans to yellow jelly beans in a dish is 3:4. if ...
Probability - A jar contains four red, four yellow, and three green jelly beans...
math - a jar of jelly beans contains 33 red, 52 white, 70 yellow ad 85 orange. ...
For Further Reading