Claire purchases a new dress for the prom. The dress is priced $160, but it is on sale for 30% off. Claire’s aunt works at the store and can give her an additional 10% off. If the sales tax is 7.5%, how much does Claire pay for the dress?

Since it's on sale and her aunt can discount it, the total discount is 40% off. Take 100 and subtract it from 40. You'll get 60. Since 40% is equal to .40, make 60 a decimal as well. .60. Take .60 and multiply it by 160. You'll get 96. Now for the tax.
Take 7.5 and ADD it to 100, giving you 107.5. Move the decimal over twice making it 1.075. Take 1.075 and multiply it by the 96 we got earlier. That gives you $103.20
The answer is $103.20