Question

You go to a local mechanic to get your tires changed. The tires cost $300. There is a 6% sales tax, but you get a 10% discount. There is also a $10 non-taxable disposal fee for your old tires, which the mechanic tells you is not subject to discount.a. Write a function, t(x) for the total purchase amount after taxes but before discounts and fees.b. Write a function, d(x) to account for the total after discounts on purchase amount x.c. Does it matter whether the mechanic adds the tax first or takes the discount first?

Answer 1

Answer:

a) $T(x)=300x+18x=318x$

b) $D(x)=318x-(0.1)(318)+10x\\=296.2x$

c) Yes.

Step-by-step explanation:

We have that:

$Tires= 300\\Tax=0.006\\Discount=0.1$

And we have $10 free of taxes.

Making x= number of tires to buy, then we have that the total cost of tires is:

$Total_{Tires}=300x$

So, what we pay for taxes is given by:

$Taxes=(300x)(0.06)=18x$

a) Then, according to the above, we can write down the total cost before the discount as:

$T(x)=300x+18x=318x$

b) And the total cost after discounts, is then given by:

$D(x)=318x-(0.1)(318)+10x\\=296.2x$

c) If the discount is added first, then less tax will be paid because the amount on which it is paid is lower. If the discount is added later, then the taxes will have been taxed on a higher amount, so it does matter whether they are added first or later.