Answer: 17$
Explanation:
There is a sales tax of $5 on an item costing $51 before tax.
So the ratio of sales tax to price before tax is the following.
$5 sales tax
$51 price before tax
A second item costs $173.40 before tax.
We have to find the sales tax, which we call Q. So we use the following proportion.
$5 sales tax = $Q sales tax
$51 price before tax $173.40 price before tax
Another way
Using the method of cross products, we solve for Q.
551 = Q173.40
51Q = ·5173.40
Q = ·5173.4051
Q = 17