Question

a jar contains 3 red, 4 blue, and 5 white marbles. What is the probability of drawing first a read and then, without replacement a white marble?

Answer 1

Probability of drawing red first =
`(number of red marble )/(total number of marbles)`

Probability of drawing red first =
`(3)/( 3 + 4 + 5)`

=
`(3)/(12)` =
`(1)/(4)`

Probability of drawing a white marble second =
`(number of white marbles )/(total number of marbles left)`

=
`(5)/( 2 + 4 + 5)`

=
`(5)/(11)`

Now, probability of drawing first a red and then, without replacement a white marble =
`(1)/(4)` ×
`(5)/(11)`

=
`(5)/(44)`