You may like to read the article on Morse code before attempting this question. Morse's letter analysis was done over 150 years ago, so might there be a better allocation of symbols today?
This short article gives an outline of the origins of Morse code and its inventor and how the frequency of letters is reflected in the code they were given.
Shifting Average
Age 11 to 14 Short Challenge Level
The average of four numbers is 48.
If 8 is subtracted from each number, what is the average of the four new numbers?