Answer:
Margie ordered a total of 18 items
Step-by-step explanation:
Margie's total cost can be expressed as;
C=(p×n)+s
where;
C=total cost
p=price per unit of skin care set
n=number of skin care sets
s=shipping fee
In our case;
C=$115.00
p=$6.00 each
n=unknown
s=$7.00
replacing;
115=(6×n)+7
6 n+7=115
6 n=115-7
6 n=108
6 n=108
n=108/6
n=18
Margie ordered a total of 18 items
