The teacher has recently set a class the following puzzle: "Write down four positive whole numbers less than 100 and then write down their average: choose the original numbers so that overall the five numbers written down use each of the digits 1 to 9 exactly once."

Three students in the class were successful. Heinrich came up with 9, 15, 36 and 48, with average 27. Felix was more cunning – his average was not a whole number – it involved a mixed fraction in its simplest form, like 27¾. Delphine was devious, too, and her average, which was lower than Felix's, was not a whole number – it involved decimals, like 16.25.

What averages did Felix and Delphine write?