An urn contains 5 black and 20 white marbles. They are to be drawn one at a time until all of one color has been exhausted.

What is the probability that the color of the first draw correctly predicts the first color exhausted?

(In reply to

re(2): solution by Charlie)

Let not be confused with the wordings:

.I SAID:..........IMHO the probability you have evaluated is the probability of matching (same color) of 1st drawn with the last of **same** color." ;

it addresses the **last i.e the exhausting one, - we do not want to continue till the end.**

All in all, continuing to read in this context I maintain that

the official solution re prediction **is 2/3, not 1/3.**

Please read the** definition of the task and revert.**