If the first ounce is already $0.22, then we have to calculate how much it cost for the remaining ounce.
![2.8oz-1oz=1.8oz](https://img.qammunity.org/2023/formulas/mathematics/college/cqq9jopc2fb5d0v6q0mzv6kt6ps5n7y4t2.png)
The remaining ounce is 1.8 oz. If each additional ounce or fraction of an ounce weighs $.17 then, 1 more ounce cost $.17 and the remaining 0.8 oz cost $.17 too.
Hence, the total cost to mail a first-class letter weighing 2.8 oz is:
![\begin{gathered} =1oz+1oz+0.8oz \\ =0.22+0.17+0.17 \\ =0.56 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/vkai2d78m84zyxpyjftahnovli4g1hukpi.png)
The total cost is $0.56. (Option A)