A television director has to schedule commercials during 6 time slots. There are four distinct commercials, A, B, C, and D. A must be aired three times but never twice consecutively.
How many ways are there to air the ads?
A television director has to schedule commercials during 6 time slots. There are four distinct commercials, A, B, C, and D. A must be aired three times but never twice consecutively.
How many ways are there to air the ads?