Verbal Reasoning - Mental Ability Questions

Which set of letters when sequentially placed at the gaps in the given letter series shall complete it?

_r_r_t_r_r_t

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
l m _ o _ n m _ l _ n _ _ n m l

If '+' means 'x' , '­' means '÷' , 'x' means '­' and '÷' means '+' , then what will be the value of 16 ÷ 4 x 10 ­ 5 + 8 = ?

In a certain code language, "DURING" is written as "GRUFQD". How is "PICKED" written in that code language?

A series is given, with one number missing. Choose the correct alternative from the given ones that will complete the series.
400, -200, 100, ? , 25, -12.5

Each  of  the  following  questions has   four   statements.   Three   are   logically correct.  Some  of  which  may  look  factually absurd.  Ignore  this  absurdity  and  look  to  the logical   corrections.   Choose   the   statement which is wrong or doubtful:-

If P denotes multiply, T denotes subtraction, M denotes addition, B denotes division then 28B7P8T6M4 = ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
RS, ZA, HI, ?