While walking around the mall, you noticed that the movie store is advertising the latest movie release on DVD for $17.99. You buy the movie and pay $19.07, because sales tax was added to the purchase price. How much is the sales tax? write and solve the equation. And draw a algebraic model.

Question

While walking around the mall, you noticed that the movie store is advertising the latest movie release on DVD for $17.99. You buy the movie and pay $19.07, because sales tax was added to the purchase price. How much is the sales tax?  write and solve the equation. And draw a algebraic model.

across · Answer

If the movie costs $17.99 but you had to pay $19.07 then that means that the sales tax was:
$$(100)(19.07)/17.99-100=6%$$6%

anonymous · Answer

did he have to multiply 100 by 19.07

across · Answer

You don't have to multiply by 100, but it comes in handy when needing to find a percentage.

anonymous · Answer

so what does(100)(19.07) mean

across · Answer

We're trying to find a _percentage_, as a result, we need to convert our numbers to that form.

across · Answer

It's the good-old rule of three:

$17.99 -> 100%
$19.07 -> x ?

Where you solve for x by cross-multiplying 19.07 by 100 and dividing the result by 17.99.

anonymous · Answer

can you draw a algebraic model