Question

There is a bag filled with 5 blue, 6 red and 2 green 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 green?

Answer 1

$\frac{2}{13}$

Let  's' be the sample  space .

S = { B₁, B₂, B₃, B₄, B₅, R₁, R₂, R₃ , R₄, R₅ ,R₆, G₁, G₂ }

n(S) = 13

A is the event that the marble picked up is a green marble .

Now there are two green marbles out of 13 marbles.

∴ A = { G₁, G₂ }

n(A) = 2

P(A) = $\frac{n(A)}{n(S)} =$$\frac{2}{13}$

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