Calculating an average on a 1/4 chance

Question

In a video game you preform an action that is guaranteed to drop one of these values: 5,10,15,20. All have an equal chance of happening (only one of the values can drop at any single completion), how would you go about calculating the average over 100 completions of said action?

Answer 1

Since the outcomes are equally likely you would expect each number to show up 25 times and the expected outcome is 25*(5+10+15+20) = 25*50 = 1250.