A letter is known to have come either from LONDON or CLIFTON. On the envelope just two consecutive letters ON are visible. What is the probability that the letter has come from LONDON ?

Explanation

To solve the problem, we need to find the probability that the letter has come from LONDON given that the visible letters are "ON". We will use Bayes' theorem for this calculation.

### Step-by-step Solution:

1. **Define Events**:
- Let \( A \) be the event that the letter is from LONDON.
- Let \( B \) be the event that the visible letters are "ON".

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