SOLUTION: A bag has 12 blue marbles and 4 red marble of equal size. Red marbles are added to the bag. One marble is randomly chosen from the bag. How many red marbles are added if the probab

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Question 947309: A bag has 12 blue marbles and 4 red marble of equal size. Red marbles are added to the bag. One marble is randomly chosen from the bag. How many red marbles are added if the probability of randomly choosing a blue marble is now 2/5/
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
The probability of choosing a blue marble is equal to the number of blue marbles divided by the total number of marbles.
P=%2812%29%2F%2812%2B4%2Bx%29=2%2F5
So then,
5%2812%29=2%2816%2Bx%29
60=32%2B2x
2x=28
x=14