(Q). In how many ways 5 distinct volume of chemistry and 7 distinct volume of Botany book can be arranged on a bookshelf such that no two chemistry books are together ?
Sol:-
•B₁•B₂•B₃•B₄•B₅•B₆•B₇•
7 distinct botany books can be arranged in 7! ways. This will create 8 spaces, marked by •(dot), to place chemistry book.
Now 5 chemistry books can be arranged in these 8 places in ⁸C₅.5! ways.
Hence total number of ways = (7!).(⁸C₅.5!) Answer
