In how many different ways can four books A, B, C, and D be arranged one above another in a vertical order such that the books A and B are never in continuous position?
In how many different ways can four books A, B, C, and D be arranged one above another in a vertical order such that the books A and B are never in continuous position?
Answer:
(b)
There are 12 arrangements where books A and B are not in continuous position.