Correct. Using the formula $\displaystyle{r}=\frac{{W}}{{t}}\usepackage{cmbright}\Huge\$ , you can create the following equation: $\displaystyle\frac{{500}}{{t}}+\frac{{500}}{{{1.5}{t}}}=\frac{{500}}{{1}}\usepackage{cmbright}\Huge\$ . Solving for t, you find $\displaystyle\frac{{{1.5}{\left({500}\right)}}}{{{1.5}{t}}}+\frac{{500}}{{{1.5}{t}}}=\frac{{{500}{\left({1.5}{t}\right)}}}{{{1.5}{t}}}\usepackage{cmbright}\Huge\$ , which simplifies to 750 + 500 = 750t. 1250 = 750t so $\displaystyle{t}={1}\frac{{2}}{{3}}\usepackage{cmbright}\Huge\$ , or 1 hour and 40 minutes.