<PRE><B>Question 955404</B>
i believe your solution is 1/12.


if every 3rd song is classic rock and every fourth song give a prize, then you will have classic rock playing and a prize given every 12th song.


this is because the least common multiple of 3 and 4 is equal to 12.


common multiples of 3 are 1,3,6,9,12,.....
common multiples of 4 are 1,4,8,12,......


12 is the least common multiple.
every 12th song will be classic rock and a prize will be given at the same time.

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