Restrictive Permutation (PrepSwift video solved question) How to solve with another method

GRE Quant Problem Solving
1

Hi, I was going through PrepSwift content and in the Restrictive permutation video, there is a question that is solved using counting method with restriction (Screenshot of question and solution in given below)

Screenshot from 2023-10-30 15-12-14
Screenshot from 2023-10-30 15-12-141681×890 81.1 KB

I agree with the method and the solution.

  • But how can I get the same answer using the concept of

Restriction = no restriction (total) - restriction is not followed

If I am correct, total number of ways to arrange these books without restriction will be 7 * 6* 5* 4 = 840
How, can I get number of ways where restriction is not followed.

Thanks for the help in advance

2

You’ll need to consider the different ways and add the up individually. For example, two consecutive novels in the first two positions.

3

Took me few attempts but I got the answer. Thank you for replying !!