Respuesta :
Let N be the total amount of whole ounces that are mailed.
Since mailing the first ounce has a cost of $0.39, then there will be N-1 ounces charged for $0.22 each.
The total cost of mailing N ounces will be:
[tex]0.39+0.22\times(N-1)[/tex]If that cost cannot exceed $7.24, then:
[tex]0.39+0.22\times(N-1)\le7.24[/tex]Solve the inequality for N:
[tex]\begin{gathered} \Rightarrow0.22\times(N-1)\le7.24-0.39 \\ \Rightarrow0.22N-0.22\le6.85 \\ \Rightarrow0.22N\le6.85+0.22 \\ \Rightarrow0.22N\le7.07 \\ \Rightarrow N\le\frac{7.07}{0.22} \\ \Rightarrow N\le32.136\ldots \end{gathered}[/tex]Since N must be a whole number, the maximum value of N that satisfies the inequality is 32.
Therefore, the maximum number of whole ounces that can be mailed for $7.24 is:
[tex]32[/tex]