I'm have trouble with a particular problem in a Geometry course from The Great Courses. I've found other errors in the course and believe this is another but it's so egregious that I wanted to check to make sure I'm not just missing something. Please take a look at the problem below:

Question 10.i asks, Use similar triangles to show that

$\displaystyle \frac{y}{y+x} = \frac{s}{s+t}$

Shouldn't that be:

$\displaystyle \frac{x}{y+x} = \frac{s}{s+t}$

Your help will be appreciated.