A survey was carried out to find out whether the mode of travel to work differed significantly between commuters aged over and under 30. 60 commuters were interviewed, half from each age group. Twice as many under 30s took a car to work compared with taking public transport and only one over 30 used public transport. 25% of the commuters walked, three-fifths of whom were over 30.
What is the probability that a motorist is under 30?