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Algebra_4
Chapter 79
Problem 2
Select a different problem
Example:
A ceramic jar contains 5 blue marbles and.
9 red marbles. A red marble is drawn
and not replaced in the jar.
Find the probability P that the next marble drawn is red.
The total number of marbles in the jar is 9 + 5 = 14.
Since the probability of drawing any marble is an independent event,
the probability P(red1) on the first draw
is equal to the number of red marbles divided by the
total number of marbles in the jar.
Thus:
=\frac{9}{9+5}=\frac{9}{14} )
For the second draw the total number of marbles in the jar is 8 + 5 = 13.
and the total number of red marbles is 8. Thus, the probability of drawing
a red marble the second time is
=\frac{8}{8+5}=\frac{8}{13} )
The probability that both marbles are red is the product of each probability.
So:
P(red2)=\frac{9}{14}\frac{8}{13}=\frac{72}{182}=\frac{36}{91} )
In decimal form:
