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`

Explanation

No. of Ways = `22_(C_19)`

=`22!/(19!*3!)`

=`22**21**20**19!/(19!*3*2*1)`

=`22**70`

=`1540`