Answer:
$98.20
Explanation:
"30% off" refers to the discount (amount by which the original price is reduced); 100% - 30%, or 70%, refers to the sale price. It's the latter that we want. Multiply $129 by 0.70 to obtain the sales price, obtaining $90.30.
The final cost to Debbie is this sales price plus the 8.75% sales tax. Multiply this $90.30 by 1.0875 to obtain the sales price: $98.20.