You may have misread the graph. The graph shows that 200 miles are traveled in 5 hours. Because this is a direct variation problem, solve for k, the constant of variation, using the equation $\displaystyle{y}={k}{x}\usepackage{cmbright}\Huge\$ , where $\displaystyle{y}={200}\usepackage{cmbright}\Huge\$ and $\displaystyle{x}={5}\usepackage{cmbright}\Huge\$ . Then use the k value in a new direct variation equation, with $\displaystyle{x}={15}\usepackage{cmbright}\Huge\$ , and solve for y.