Stan likes music, and likes oldies the best. In his collection of music he has a cassette tape of “The Cassettes 20 Greatest Hits”. The amazing thing about the 20 Greatest Hits, is that each hit is exactly 3 minutes long. This fits perfectly on a 60-minute tape.

Songs 1 – 10 are on Side A, while 11 – 20 are on Side B. When listening to the tape, Stan does one strange thing. He listens to the first 5 songs on side A, then flips it to the other side. He then listens to Side B from that point until the tape ends. How many songs does Stan hear?

• The tape is wrapped around two spools that have identical diameters of 1 cm.
• The spool that is receiving the tape rotates at a constant speed.
• The tape, when located all on one spool, measures 5 cm in diameter.

I think the person who submitted the puzzle gave way more info than was needed.  I still say it's ten songs.

If you are playing side A of the tape as described above, and one three minute song plays, that means that side B of the tape is rewinding three minutes worth of tape. 

Disagree?  Well, if you play all ten songs on Side A, you've played  3x10 minutes.  and side B will have rewound 30 minutes worth of tape.  Right?  So why would 1 song, 2 songs, or 3 songs be any different?  Playing X number of songs on side A means X number of songs are rewound on side B.

One reason I know this is because I used to make tapes of single songs.  We would record the song, then immediately pop the tape out, flip it over, and record it again on the other side without rewinding or fast forwarding to the end of the tape. 

You did this so that as soon as the song finished playing on side A, you flipped the tape over and the same song would be ready to start on side B.  And then when side B was done, you flipped it over again, etc.  It prevented having to rewind each time.  Playing the song of side A automatically rewound the tape on side B to the proper position.

Posted by Lisa on 2004-04-29 11:28:42