25) From a bag containing 4 white and 6 red balls, three balls are drawn at random and if cash white
ball drawn carries a reward of Rs. 4 and each red ball Rs. 6, find the expected reward of the draw.
Answers
Answered by
6
Answer:
Given a bag contains 6 white and 4 red balls.
∴ The sample space is S=6+4=10
One ball is red and two balls are white.
CaseI: If red ball is drawn at first position and then the white balls
P=
10
6
×
9
4
×
8
3
=
10×9×8
6×4×3
=
10
1
CaseII: If red ball is drawn at second position and then the white balls correspondingly
P=
10
4
×
9
6
×
8
3
=
10×9×8
4×6×3
=
10
1
CaseIII: If red ball is drawn at third position
P=
10
4
×
9
3
×
8
6
=
10×9×8
4×3×6
=
10
1
∴ Probability of one ball is red and two balls are white=
10
1
+
10
1
+
10
1
=
10
3
Similar questions