You find a sales receipt from a store that shows the total price as $40, and the total amount paid including sales tax as $42.
a. Write an equation you can use to find the sales tax rate r.
100 [(42 - 40) / 40] = r
To find the sales tax rate r, we need to set up an equation that relates the total price and the total amount paid including sales tax.
Let's assume the original total price before adding sales tax is P, and the sales tax rate is r.
Since the total amount paid including sales tax is $42, we can write the equation:
P + (P * r) = $42
In this equation, P represents the total price, (P * r) represents the sales tax amount, and $42 represents the total amount paid including sales tax.