Imagine I am marketing a new brand of yoghurt called yogorlicious and I ask 100 yoghurt shoppers two questions:

1) Age (either young or old). Assume that young means <30 and old means 30+.

2) Do you prefer yogorlicious over your current brand (Yes or No)

Assume there were 37 old people and 17 of them preferred yogorlicious. Of the young people, 12 of them preferred yogorlicious.

What is the probability that a shopper chosen at random prefers yogorlicious over their current brand (calculate your answer to 2 dp)?