You are buying potato chips at the grocery store. you have a manufacturers coupon for a $1.00 off and the store is offering 20% off if you buy 2 bags. you decide to buy 2 bags of potato chips. how do you compute your final cost?

a. subtract $1.00 off each bag and then multiply by .20
b. multiply each bag by .20, subtract $1.00 off of each bag, and then add them together.
c. add the two bags together, multiply by .80, and then subtract $1.00.
d. subtract $1.00 from the first bag, then add them together, and then multiply by .80.