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 #14 on page 76: “If a is the smallest prime number greater than 21 and b is the largest prime number less than 16,…”
Verbal: Section 3, Question #14 on page 55: a question on the passage about Russian serfom that begins, “The sentence “In the argument given, the two portions in boldface play…”