Here’s another set of video explanations (one math, one verbal) of practice problems found in ETS’s Paper-based Practice Test for the Revised GRE, a PDF released by the test-makers themselves.
You can find the whole set of explanations for every practice problem here. Enjoy!
Math: Section 5, Question #4 on page 72 that begins, “A power station is located on the boundary…”
Verbal: Section 3, Question #4 on page 51 that begins, “The (i)____ nature of classical tragedy in Athens…”