Question

These marbles are placed in a bag and two

of them are randomly drawn.
What is the probability of drawing two pink
marbles if the first one is NOT placed back
into
the bag before the second draw?
Give your answer as a rational number, reduced to
simplest terms.
Hint: Multiply the probability of the 1st Event by the
probability of the 2nd Event to get your answer.​

Answer 1

`Pr = (1)/(45)`

Explanation:

Given

`Black =5`

`Pink = 2`

`Blue = 3`

Required

`P(Pink\ and\ Pink)`

This is calculated as:

`Pr = P(Pink) * P(Pink)`

Because it is a selection without replacement, the probability is:

`Pr = (n(Pink))/(Total) * (n(Pink) - 1)/(Total - 1)`

`Pr = (2)/(10) * (2 - 1)/(10 - 1)`

`Pr = (2)/(10) * (1)/(9)`

`Pr = (1)/(5) * (1)/(9)`

`Pr = (1)/(45)`