Well if her coupon is $3 off you add that to the remaining total. If we aren’t including tax and and we assume that both types of calzone are the same price then 12.49/2 is about $6.25
You mention "a calzone," which indicates that there's just one.
If, after $3 is taken off the the bill, the price is $9.49, we merely add $3 to that to obtain the regular price of "the calzone." That comes to $12.49.
