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 #10 on page 76: a Numeric Entry problem that says, “If x and y satisfy the system of equations above…”
Verbal: Section 3, Question #10 on page 54 that begins, “In which sentence of the passage does the author provide examples…”