A certain calling card gives the following rate to Malaysia. There is a connection fee of $0.39 which allows you to connect for up to (but not including) a minute. For each additional minute or part of a minute, there is a $0.24 cent charge. (For example, for 1 minute up to but not including 2 minutes costs $0.63.) You need to make a 20 minute call.

Express this information as a function, where f(x) represents the amount of money charged and x represents the number of minutes which have elapsed.