A bag contains 8 red and 5 white balls. 2 balls are drawn at random. What is the probability that both are white ?
A bag contains 8 red and 5 white balls. 2 balls are drawn at random. What is the probability that both are white ?
A. 5/16
B. 2/13
C. 3/26
D. 5/39
Answer : D. 5/39
Explanation:
- n(S) = Number of methods for drawing 2 balls out of 13 = 13C2
= (13 x 12) / 2
= 78. - n(E) = No. of methods for drawing 2 balls out of 5 = 5C2
= (5 x 4) / 2
= 10. - Therefore, P(E) = n(E) / n(S)
= 10/78
= 5/39.
