One bottle of sunscreen costs $4.50.
Let's use b to represent the bottles of sunscreen and h for the hat.
The information in the problem yields this equation:
The tricky part is understanding the 1.06 coefficient. If there is a 6% sales tax on top of the total price, that is the same as multiplying the price by 1.06 (itself plus 6% more).
Now we can divide both sides by 1.06 to get a simpler equation:
Last, we plug in the hat's price and solve for b: