Answer: the pre-tax subtotal is $330
Step-by-step explanation:
Let x represent the pre tax total
If the tax rate in the area is 8.2%, it means that the amount of tax paid is
8.2/100 * x = 0.082x
pretax total + tax = after tax subtotal
Given that after tax subtotal is $357.06, then
x + 0.082x = 357.06
1.082x = 357.06
x = 357.06/1.082
x = 330
the pre-tax subtotal is $330