The formula in computing the simple interest of a savings account is:
I = Prt
Where I = interest earned
P = principal amount deposited
r = rate
t = time in years
You are asked to find the total amount of interest earned at the end of 5 years. Substituting the amounts to the formula:
I = $500 (4%) (5)
I = $100
Therefore, the total amount of interest earned at the end of 5 years is $100.