Question

taking out 3 balls simultaneously from a bag containing 4 red and 5 green balls . find sample space

Answer 1

Step 1:

Given a bag contains 8 red and 5 white balls

∴ The sample space is S=13(8+5)

Step 2:

One ball is red and two balls are white

Three cases arise in this situation

Case I:

If red balls is drawn at first position and then the white balls

P=813×512×411

=403×143

Step 3:

Case II:

If red ball is drawn at second position and then the white balls correspondingly.

P=513×812×411

=403×143

Step 4:

Case III:

If red ball is drawn at third position

P=513×412×811

=403×143

Step 5:

P[one ball is red and two balls are white]

⇒403×143+403×143+403×143

⇒3×403×143

⇒40143

Answer 2

bag contain 4red balls 5green balls
sample space S=4+5
=9
let A be the event of taking 3 balls
so n(A)=3
p(A)=n(A)/n(S)
=3/9
1/3