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There are 8 blue marbles and 7 red marbles in a bag. Julie pulls two marbles at random from the bag first. What is the probability that she first pulls a blue marble and then a red marble?

User Xagaffar
by
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2 Answers

2 votes

Answer:

either a ratio 8;7. or a percentage of 53% for picking the blue marble first i think and a 50/50 chance if you keep that blue marble out.

Explanation:


User EddyTheB
by
7.9k points
6 votes

Answer:
(4)/(15)

Explanation:

Given: Number of blue marbles = 8

Number of red marbles = 7

Total number of marbles = 8+7=15

Now, the probability that she first pulls a blue marble is given by :-


P(B)=\frac{\text{blue marbles}}{\text{Total marbles}}\\\\=(8)/(15)

Now, total marbles left in bag = 15-1=14

Now, the probability that she second pulls a red marble is given by :-


P(B)=\frac{\text{red marbles}}{\text{Total marbles left}}\\\\=(7)/(14)=(1)/(2)

Thus, the probability that she first pulls a blue marble and then a red marble is given by :-


P(B)*P(R)=(8)/(15)*(1)/(2)=(4)/(15)

User Nikolay Elenkov
by
9.2k points

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