Given that the basket of watermelons sells for $9 before tax and the tax rate is 9%.
The tax on the basket of watermelons is given by

Therefore, the total price Tiffany pays for the basket of watermelons is $9 + $0.81 = $9.81
100-25 = 75
540 x 0.75=405
405x 0.06 = 24.3
405- 24.3 =380.7
7 ig because I mean if you take a look at the problem