Charles has decided to open a? lawn-mowing company. To do? so, he purchases mowing equipment for ?$6,000?, buys gasoline?($2.10 in gas is required to mow each? yard), and pays a helper ?$20.00 per yard. Prior to opening the lawn? company, Charles earned ?$5,000 as a lifeguard at the neighborhood swimming pool. Assume the money he used to purchase the mowing equipment could otherwise have earned 5 percent per year in the bank and that the mowing equipment depreciates at 20 percent per year. Charles plans to mow 300yards per year. Charles's implicit cost of production is $ per year?