You buy six notebooks and a backpack. The cost of the backpack is$ 17.90. You pay 6% in sales tax. Your total bill is $30.74 how much does each notebook cost?

Set this up as an equation to start out. We'll call the a notebook n.

First you need to subtract the sales tax from the total price ... 30.74 - (30.74*.06) = 17.9 + 6n

Simplify

28.92 = 17.9 + 6n

Subtract 17.9 from both sides.

11.02 = 6n

Divide both sides by 6

1.8367 = n (so this is the cost of 1 notebook.)