Answer: $9.81
Explanation:
Given : Tiffany buys a basket of watermelons on sale for $9.
I.e. Cost of a basket of watermelons = $9
Sales tax = 9% = 0.09 [ we divide percentage by 100 to convert it into decimal]
Now , the Total price Tiffany paid = (Cost of a basket of watermelons ) + (Sales tax) x (Cost of a basket of watermelons )
= $9 + (0.09) ($9)
=$9 (1+0.09)
=$9 (1.09)
= $9.81
Hence, the total price Tiffany pays for the basket of watermelons is $9.81.