There are two parcels, one marked CALCUTTA and one marked TATANAGAR which get lost in transit.
One parcel is found and has the label partly torn (the label can be torn in any manner). It only has the letters 'TA' (adjacent letters).
What is the probability that the recovered parcel was marked CALCUTTA?
One might say that "TA" occurs alone three times in the two labels, only once in "Calcutta", giving a probability of 1/3. However, I think it is simpler to say that there are two parcels, and the label is from one or the other, so I think the probability should be given as 1/2 for each one. Presumably, the other parcel is still in transit, otherwise one would know for certain which one was recovered with the torn label. We don't have any data on senders, receivers, or transit service, to know who might be making the guesses.