TS EAMCET 11-Sep-2020 Shift 2 Solved Paper

Let Ai(i=1,2,3,4) be the event that the urn contains 2,3,4 or 5 white ball and the event that two white ball are drawn.
We have to find P(A4/B)
Since the four events A1,A2,A3,A4 are equally
likely, we have P(B/A1) is the probability of event that the urn contains 2 white balls and both have been drawn.
Hence, ‌‌P(B/A1)=‌

2C2

5C2

=‌

1

10

Similarly, P(B/A2)=‌

3C2

5C2

=‌

3

10

∴ From the Baye's theorem
P(A4/B)=‌

1

2