Question

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?

Answer 1

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.

Step-by-step explanation:

Answer 2

Answer: $\frac{4}{15}$

Step-by-step 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 :-

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

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

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

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

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

$P(B)\timesP(R)=\frac{8}{15}\times\frac{1}{2}=\frac{4}{15}$