Question

There is a bag filled with 5 blue and 4 red marbles. A marble is taken at random from the bag, the colour is noted and then it is replaced. Another marble is taken at random. What is the probability of getting exactly 1 blue?

Answer 1

Answer:

5 out of 9

Step-by-step explanation:

You have 5 blue marbles and for red marbles which makes a total of 9 marbles in a bag. If you take one marble out and put it back in another marble out and put it back at random the probability of getting a blue marble is 5 out of 9.

Answer 2

The probability of getting exactly 1 blue marble from a bag which is  filled with 5 blue and 4 red marbles is 40/81.

What is probability?

Probability of an event is the ratio of number of favorable outcome to the total number of outcome of that event.

There is a bag filled with 5 blue and 4 red marbles. Thus, the total number of marble in the bag are,

$5+4=9$

One marble is taken at random from the bag, the color is noted and then it is replaced. The probability of getting blue marble is,

$P(B)=\dfrac{5}{9}$

The probability of getting red marble is,

$P(R)=\dfrac{4}{9}$

The Probability of getting red marble in first pick and  probability of getting blue marble in second pick is,

$P_1=\dfrac{4}{9}\times\dfrac{5}{9}=\dfrac{20}{81}$

The Probability of getting blue marble in first pick and probability of getting red marble in second pick is,

$P_2=\dfrac{5}{9}\times\dfrac{4}{9}=\dfrac{20}{81}$

The exactly 1 blue is taken out, when first marble is red and second is blue or the first one is blue and second one is red. Thus, the probability of getting exactly 1 blue is,

$P=P_1+P_2\\P=\dfrac{20}{81}+\dfrac{20}{81}\\P=\dfrac{40}{81}$

Thus, the probability of getting exactly 1 blue marble from a bag which is  filled with 5 blue and 4 red marbles is 40/81.

Learn more about the probability here;

https://brainly.com/question/24756209

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