Can you solve the MAGNET RIDDLE? ft YouTube CEO Susan Wojcicki

Answer to the riddle: test the force of attraction between the iron bars. Drop one, which would reduce it's magnetism if it were magnetic, and re-test the attraction. if the attraction is reduced, then the bar you dropped is the magnetized bar. If not, drop the other one and re-test. Dropping the second one allows you to verify your hypothesis that the setup used to drop the magnets has a sufficient shock to reduce the magnetism in the iron. (you could also use the mallet instead of dropping, but I liked the idea of using no tools at all)