Step-by-step explanation:
I assume we are ignoring holidays, vacation days, sick days,...
then we have 52 weeks in a year with 5 works days each.
so, 52×5 work days in a year = 260 work days per year.
every work day he saves 5.76 - 3.75 = $2.01
so, he saves over the course of a year
260×2.01 = $522.60