We have to use the simple interest formula
[tex]A=P(1+rt)[/tex]Where P = 70,600 tons, r = 0.07 (7%), and t = 18 years. Let's replace these values
[tex]\begin{gathered} A=70,600\cdot(1+0.07\cdot18)=70,600(1+1.26) \\ A=70,600(2.26)=159,556 \end{gathered}[/tex]