There are 10 persons named . Out of 10 persons, 5 persons are to be arranged in a line such that in each arrangement P1 must occur whereas P4 and P5 do not occur. Find the number of such possible arrangements. [Hint: Required number of arrangement ]
Given that
persons out of which 5 are to be arranged but must occur
whereas P4and P5 never occur. So, now we only have to select 4 out of 7 persons
Number of selections=
Number of the arrangement of 5 persons=