Final answer:
The total cost of the floral arrangement is $17.23.
Step-by-step explanation:
To calculate the total cost of a floral arrangement with a retail cost of $15.99 and a tax rate of 7.775%, we need to add the tax amount to the retail cost. First, we calculate the tax amount by multiplying the retail cost by the tax rate: $15.99 x 0.07775 = $1.24. Then, we add the tax amount to the retail cost to find the total cost: $15.99 + $1.24 = $17.23.
Learn more about calculating total cost with tax