Answer:
The price per book that Mary purchased is $12
Step-by-step explanation:
Mary's total cost can be expressed as;
C=(p×n)+s
where;
C=total cost
p=price per unit of books
n=number of books purchased
s=shipping fee
In our case;
C=$55.25
p=unknown
n=4
s=$7.25
replacing;
55.25=(4×p)+7.25
4 p+7.25=55.25
4 p=55.25-7.25
4 p=48
p=48/4
p=12
The price per book that Mary purchased is $12
