here i m taken each possible case. case1-> A->epsilon(Null prod) and A-> B (Unit prod.) not allowed then for 'n' length token how many maximum reduce move required . lets take example - for string 'ab' S->AB : A->a , B->b then here required 3 reduced moves . lets take other string ex- abc for that i do S->AB , A->DE , D->a , E->b ,B->c so it is 5 so we can say in general answer will be 2n-1
case 2 . if A-> epsilon(Null prod) and A-> a are not allowed but unit production allowed then for that if i take string 'ab' then for that S->A , A->B, C->D, D->E and so on ..at last producion i write like as K->ab so here for that we can't write a general form .
case3. if A-> epsilon(Null prod) and A-> a are not allowed and also unit production not allowed then take string 'ab' for that you can write only S->ab for that required 1 reduce and for string 'abcd' we can write S->AB , A->ab ,C->cd so required 3 so in general required 'n-1' reduce . then according to arjun sir no need to be change the question so i m going wid "n-1"