If the price of one candy bar is $1.29, for every weekday we have a total of 5 candy bars, so the cost will be:
[tex]\text{cost}=5\cdot1.29=6.45[/tex]In a month we have 30 days, and 5/7 of these days are weekdays, so the cost will be:
[tex]\text{cost}=(30\cdot\frac{5}{7})\cdot1.29=27.64[/tex]In a year we have 365 days, and 5/7 of these days are weekdays, so the cost will be:
[tex]\text{cost}=(365\cdot\frac{5}{7})\cdot1.29=336.32[/tex]