Incorrect. You can use this system to solve the problem for t, time:

$\displaystyle{d}={30}{t}\usepackage{cmbright}\Huge\$

$\displaystyle{35}-{d}={40}{t}\usepackage{cmbright}\Huge\$

Now use either the substitution or elimination method to solve for t. What do you find? (Remember that t will be in terms of hours, not minutes!)