Connie Paid a sales tax of 8 percent

[DennaMueller]

Connie Paid a sales tax of 8 percent on her purchase. If the sales tax had been only 5%, she would have paid $12 less in sales tax on her purchase. What was the total amount that Connie paid for her purchase including sales tax?

368
380
400
420
432

I actually got this problem right by picking numbers, but I would like to know how to set up an equation.

The answer is 432

[tomslawsky]

1) Solve for price:

P(.08)= (.05P)-12

P=400

2) add sales tax:

400(1.08) = 432

[Ben Ku]

Tom, Good approach on this problem.

If we let x be the purchase price, then the tax at 8% is 0.08x, and the tax at 5% is 0.05x. That is how the first equation is set up:
0.08x = 0.05x + 12
So x = 400.

Now she paid a sales tax of 8%, which is 0.08*400 = 32, so her total price is $432.

Hope that helps!

[hatemeall143]

Hi tomslawsky

your approach is wrong
bcaz P(.08)= (.05P)+12

or P(.05)=P(.08)-12

[RonPurewal]

yes, you are correct; tom's approach is backwards (although the correct approach is probably obvious to anyone who's looking). thanks.