Abag contains 9 blue marbles and 3 red marbles. two marbles are drawn at random and at the same time. what is the probability of getting two blue marbles

The total number of marbles in the bag are 12 (9 blue marbles and 3 red marbles).

Let "A" be the event that both the drawn marbles are blue.

Therefore, if two marbles are drawn at random and at the same time, then the probability of getting two blue marbles can be calculated as:

This can also be expressed in terms of percentage as:

%

Thus, the required probability is either: or 75%

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: