SOLUTION: A jar contains 9 blue marbles and 13 green marbles. Two marbles are picked in sequence from the jar. Find the probibility that the second marble is green given that the first marbl

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Question 354181: A jar contains 9 blue marbles and 13 green marbles. Two marbles are picked in sequence from the jar. Find the probibility that the second marble is green given that the first marble is blue(assume that the first marble is not replaced).
Please help! This is one of the 2 questions out of 25 that i must explain how to do, and I have no idea.
Thank-you so much
Found 2 solutions by ewatrrr, Edwin McCravy:
Answer by ewatrrr(24785)   (Show Source): You can put this solution on YOUR website!
Hi,
*Note: There are "22 total marbles" in the jar
9 blue and 13 green
.
P( of first being blue) = 9/22
.
Note: NO replacement. There are now "21 total marbles in the jar
P(of a green being chosen) = 13/21
.
The probability of first blue AND second green is;
Answer by Edwin McCravy(20060)   (Show Source): You can put this solution on YOUR website!
A jar contains 9 blue marbles and 13 green marbles. Two marbles are picked in
sequence from the jar. Find the probibility that the second marble is green
given that the first marble is blue(assume that the first marble is not
replaced).
There are 9+13 or 22 marbles.  So 9 twenty-seconds, (nds) of the time
we will select a blue marble first.

If we then don't replace it, then after picking that blue marble, there will
remain only 8 blue marbles and 13 green marbles, or 8+13 or 20 marbles.  

Then 13 twenty-firsts (sts) of those times when we pick a blue
marble first, we will pick a green marble second.

So the answer is gotten by taking sts of those nds of the
times when we pick a blue marble first.  So the answer is





   





   

Edwin
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