While watching a game of Champions League football in a cafe, you observe someone who is clearly supporting Liverpool in the game

While watching a game of Champions League football in a cafe, you observe someone

who is clearly supporting Liverpool in the game.

What is the probability that they were actually born within 20 miles of Liverpool city?

Assume that:

• the probability that a randomly selected person in a typical local bar environment is born

within 20 miles of Liverpool is 1/20

and;

• the chance that a person born within 20 miles of Liverpool actually supports Liverpool team

is 7/10

;

• the probability that a person not born within 20 miles of Liverpool supports Liverpool team

with probability 1/10