Appendix A - Review - A.8 Problem Solving: Interest, Mixture, Uniform Motion, Constant Rate Job Applications - A.8 Assess Your Understanding - Page A69: 18

$R=250 x, $ where .$R$ is the total revenue, $x$ is the number of dishwashers sold

Let the total revenue derived be $R$ and the number of dishwashers sold be $x$. Total variable cost $=250\times $ number of dishwashers. The mathematical equation is $R=250\times x=250x$