An urn contains 5 red and 2 green balls. A ball is drawn at random from the urn. If the drawn ball is green, then a red ball is added to the urn and if the drawn ball is red, then a green ball is added to the urn; the original ball is not returned to the urn. Now, a second ball is drawn at random from it. The probability that the second ball is red, is:
(A) 26/49
(B) 32/49
(C) 27/49
(D) 21/49
Answers
Answered by
1
Answer:
32/47
Step-by-step explanation:
We start with 5R and 2G
Probability of picking a red ball = 5/7
Probability of picking a green ball = 2/7
If the drawn ball is green, then a red ball is added to the urn
New number of balls = 6R and 1G
Probability of picking red = 6/7
If the drawn ball is red, then a green ball is added to the urn
New number of balls = 4R and 3G
Probability of picking red = 4/7
Probability of the second ball being red
= 5/7x4/7 + 2/7x6/7
= 20/49 + 12/49
= 32/49
Similar questions