You may have misread the graph. The graph shows that 100 miles are traveled at 50 miles per hour. Because this is a direct variation problem, solve for k, the constant of variation. Use the equation $\displaystyle{y}={k}{x}\usepackage{cmbright}\Huge\$ , where $\displaystyle{y}={100}\usepackage{cmbright}\Huge\$ and $\displaystyle{x}={50}\usepackage{cmbright}\Huge\$ . Then use the k value in a new direct variation equation, with $\displaystyle{x}={100}\usepackage{cmbright}\Huge\$ , and solve for y. The correct answer is 200 miles.