Incorrect. The information gives you two equations:

$\displaystyle{y}-{x}={26}\usepackage{cmbright}\Huge\$ and $\displaystyle\frac{{{x}+{y}}}{{2}}={68}\usepackage{cmbright}\Huge\$

Multiply the second equation by 2 and add this to the first equation. Solve for y. Substitute into any equation and solve for x. The correct answer is 55.