Anna has a bag that contain 5 balls and Bob has a bag that contain 3 balls. Anna's bag contains 2 red balls, 1green, 1 yellow, and 1 violet ball, Bob's bag contains 2 black balls and 1 orange ball. Anna randomly chooses 1 ball from her bag and puts it into bob's bag. Bob then randomly chooses 1 ball from his bag and puts it into Anna's bag. Again, Anna radomly chooses 1 ball from her bag and puts it into Bob's bag. After these exchages, there are 4 balls in each bag. what is the probability that each bag contains exactly 3 different colour of balls?
Emergency Question !!! Please help
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blamocur
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... and what are all those people doing on the left side of the screen ?
oops... and what are all those people doing on the left side of the screen ?
Steven G
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left side?... and what are all those people doing on the left side of the screen ?
blamocur
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They must have moved since I first noticed them
Steven G
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If you insist.They must have moved since I first noticed them
Two initial comments.
Hard problems require thinking before even starting to calculate. You need to figure out what needs to be calculated first.
Particularly in probability, it is sometimes easier to calculate the probability of what we don’t want before calculating the probability of what we DO want. Why?
What we don’t want is Anna with two red balls or Anna with two black balls or Bob with two red balls or Bob with two black balls.
But that means we want Anna to have exactly one black ball and exactly one red ball. What sequences of events give that as a result?
Anna hands over a red ball, gets a black ball in return, and gives back a ball that is neither red nor black.
Anna hands over a ball that is not red, gets a black ball in return, and gives back a red ball.
Now calculate.
Thinking comes before calculating.
Hard problems require thinking before even starting to calculate. You need to figure out what needs to be calculated first.
Particularly in probability, it is sometimes easier to calculate the probability of what we don’t want before calculating the probability of what we DO want. Why?
What we don’t want is Anna with two red balls or Anna with two black balls or Bob with two red balls or Bob with two black balls.
But that means we want Anna to have exactly one black ball and exactly one red ball. What sequences of events give that as a result?
Anna hands over a red ball, gets a black ball in return, and gives back a ball that is neither red nor black.
Anna hands over a ball that is not red, gets a black ball in return, and gives back a red ball.
Now calculate.
Thinking comes before calculating.