Incorrect. If she travels 90 miles in one day, then she will travel $\displaystyle{90}{x}\usepackage{cmbright}\Huge\$ miles in x days. This will leave her with $\displaystyle{y}={3},{150}-{90}{x}\usepackage{cmbright}\Huge\$ miles to travel after x days.You need to find the number of miles left to travel when $\displaystyle{x}={20}\usepackage{cmbright}\Huge\$ .