Let \(M\) be the event that Mumbok is chosen, and \(18{-}60\) be the event that a person aged between 18 and 60 is chosen.

The probability of choosing Mumbok and a person aged 18 to 60 is:

\(P(M \cap 18{-}60) = 0.6 \times \frac{55}{90} = 0.367 \text{ or } \frac{11}{30}\)

The probability of choosing a person aged 18 to 60 from either town is:

\(P(18{-}60) = 0.6 \times \frac{55}{90} + 0.4 \times \frac{95}{160} = \frac{29}{48} \text{ or } 0.604\)

Using Bayes' theorem, the probability that the town chosen was Mumbok given that the person is aged 18 to 60 is:

\(P(M \mid 18{-}60) = \frac{P(M \cap 18{-}60)}{P(18{-}60)} = \frac{\frac{11}{30}}{\frac{29}{48}} = \frac{88}{145} \text{ or } 0.607\)