Crack a book | English idiom #shorts

Crack is

Cracking

In how many ways can 10 books on English and 8 books on physics be placed in a row on a shelf so that two books on physics may not be together?

In how many ways can 21 books on English and 19 books on Hindi be placed in a row on a shelf so that two books on Hindi may not be together? (A) 770 (B) 385 (C) 1540 (D) 399

In how many ways can 19 indentical books on English and 17 identical books on Hindi be placed in a row on a shelf so that two books on Hindi may not be together ?

In a school library, there are 780 books of English and 364 books of Science. Ms. Yakang, the librarian of the school wants to store these books in shelves such that each shelf should have the same number of books of each subject. What should be the minimum number of books in each shelf?