Chapter 2 - Equations, Inequalities, and Problem Solving - 2.4 Applications with Percent - 2.4 Exercise Set - Page 109: 58

$40$

Typical percentage problem: What percent ($n$, as a decimal number) of (the base amount $y)$ is $x?$ Translated:$\quad n\cdot y=x$ --- Here, reworded, $ 2\%$ of ($y=?$) is ($x=0.8$)$?$ Translated:$\quad 0.02\cdot y=0.8$ ($ 2\%$ converted to decimal notation is $0.02)$ ... divide the last equation with $0.02$ $y=\displaystyle \frac{0.8}{0.02}=40$