You have decided that you could save a significant amount of money riding your bike to work when the weather is good. You live in Wisconsin and estimate that the weather will be warm enough for biking 40 weeks per year. You won't bike when the forecast is for rain and you estimate rain in the forecast 1 day out of 5 per workday.

You normally drive 8 miles to work each day (round trip). Assume it costs you $0.50 per mile to drive to work. How much will you save each year by riding your bike when the weather permits?