Gramophone RecordTrick brain teasers appear difficult at first, but they have a trick that makes them really easy.
Mad Ade has found an old style gramophone type record player, along with several 12 inch gramophone records to go with it, including the all time classic, "Stig O'Tonedeaf Hums the theme from M.A.S.H !". Each disc has a 4 inch diameter middle section and a quarter inch outer border. Ignoring the fact that the discs have only a single spiralling groove, but measuring from the outer edge inwards, Mad Ade determines that there are 100 separate grooves per inch on the remaining playing surface. How far does the needle travel during one complete play of one side of the record?
AnswerThe needle only travels 3.75 inches, as it really only moves from the outer edge of the record to the middle piece.
See another brain teaser just like this one...
Or, just get a random brain teaser
If you become a registered user you can vote on this brain teaser, keep track of
which ones you have seen, and even make your own.
Back to Top