SOLUTION: There is a bag filled with 3 blue and 4 red marbles. A marble is taken at random from the bag, the colour is noted and then it is replaced. Another marble is taken at random.

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Question 1131632: There is a bag filled with 3 blue and 4 red marbles.
A marble is taken at random from the bag, the colour is noted and then it is replaced.
Another marble is taken at random.
What is the probability of getting 2 blues?

Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
.
There is a bag filled with 3 blue and 4 red marbles.
A marble is taken at random from the bag, the color is noted and then highlight%28cross%28it%29%29 the ball is highlight%28cross%28replaced%29%29 returned back to the bag.
Another marble is taken at random.
What is the probability of getting 2 blues?
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ANSWER.  %283%2F%283%2B4%29%29%2A%283%2F%283%2B4%29%29 = %283%2F7%29%5E2 = 9%2F49.


The formula is self-explanatory.