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 #13 on page 76 that begins: “In the sunshine, an upright pole 12 feet tall is casting a shadow 8 feet long…”
Verbal: Section 3, Question #13 on page 55: a question on the passage about Russian serfom that begins, “The sentence “If serfs…estate” (lines 10-11) has which of the following functions…”