Well Average is another word for Mean.
In order to find the mean of a set of numbers we need to add them together and divide by the number of numbers we have.
So lets solve.
22.10 + 13.45 + 25.10 +17.20 + 19.10 = 96.95
Now we have to divide by 5 since we have five different numbers.
96.95 ÷ 5 = 19.39
The average of this set of numbers is 19.39
Good Luck! :)