A bag contains 4 orange balls and 5 purple balls. Raina draws three balls out of the bag, one at a time, without replacement. What is the probability that the colors of the balls alternate?
+23245 This could be done in two ways: orange - purple - orange or purple - orange - purple
orange - purple - orange = (4/9) x (5/9) x (3/9) = 60/729
purple - orange - purple = (5/9) x (4/9) x (4/9) = 80/729
To find the final probability, add these two probabilities together.
I tried that but it didn't work, I don't know what could have gone wrong, it looks like the right answer to me.
+118609 A bag contains 4 orange balls and 5 purple balls. Raina draws three balls out of the bag, one at a time, without replacement. What is the probability that the colors of the balls alternate?
e.g.
P(pop) = \(\frac{5}{9}*\frac{4}{8}*\frac{4}{7}\)
The numbers get smaller as the balls are removed.
For instance if there are 4 orange, and 5 purple balls and you remove a purple one
then for the next drawer there is only 4 orange, 4 purple and 8 altogether.
So the answer is 5/9 * 4/8 * 4/7? Which is 10/63 which is wrong. Maybe because in geno's solution, he added the probabilities together, but in yours you didnt?
