Margie ordered sets of skin care products for $6.00 each and paid a flat shipping fee of $7.00. Her total cost was $115.00. How many items did she order

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