The total cost of an item including sales tax is directly proportional to its price. If the total cost of a $24 item is $25.44, what is the total cost on a $75 item?

Question

wedge38 · Answer

Direct proportionality implies a linear relation. In this case dividing 25.44/24 results with a value of 1.06. Meaning if you multiply 24 by 1.06 you will get 25.44. This is also true for any other price since the tax is directly proportional. Therefore any other item will be multiplied by 1.06 to get the total cost.

A $75 item multiplied by 1.06 will result with a $79.5 total cost.