A bag contains only red and blue marbles. Yasmine takes one marble at random from the bag. The probability that she takes a red marble is 1 in 5. Yasmine returns the marble to the bag and adds five more red marbles to the bag. The probability that she takes one red marble at random is now 1 in 3. How many red marbles were originally in the bag? terima kasih

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Jawapan

2016-06-17T19:31:58+08:00
(1x+5)/(5x+5) = 1/3
3 (1x+5)=1 (5x+5)
3x+15=5x+5
10=2x
x=5
The number of marbles before adding additional marbles is 5.
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