60 comes from the electrical grid - 20th century TV used the electrical grid to sync rather than forcing every TV to have a perfectly synced clock. Regions that

60 comes from the electrical grid - 20th century TV used the electrical grid to sync rather than forcing every TV to have a perfectly synced clock. Regions that didn't have 60Hz electrical grids used other standard framerates. 24 comes from the first "talkies" that had syncronized sound - it was the lowest framerate that sounded good. Before that, silent films were often at lower framerates to reduce the cost of film.