Incorrect. Use the formula $\displaystyle{r}=\frac{{W}}{{t}}\usepackage{cmbright}\Huge\$ to create an equation relating the individual and total work done. One way is to represent it like this: $\displaystyle\frac{{500}}{{t}}+\frac{{500}}{{{1.5}{t}}}=\frac{{500}}{{1}}\usepackage{cmbright}\Huge\$ . Now solve for t.