Answer:
$0.25
Step-by-step explanation:
to find the amount bookstore A sales after the 20% discount, cross multiply x/15.25=20/100 and you get $3.05. 15.25-3.05 gives you $12.2. substract 12.2 from 12.45 and you get $0.25. book B costs $0.25 more than book A.