Verbal Reasoning - Mental Ability Questions

In the following question, select the related word pair from the given alternatives.

House : Servant : : ? : ?

Insert the missing character depicted by '?'

In the following question, select the related letter/letters from the given alternatives.

STM : RSL : : VSF : ?

From the word 'ASTOUNDER', how many independent words can be made with-out changing the order of the letters and using each letter only once ? 

In the following question, select the related letter pair from the given alternatives.

GSR : HTP : : ? : ?

In the following question, select the related letter/letters from the given alternatives.

IMO : PTV : : KOQ : ?

If @ means +, # means -, $ means x and * means /, then what is the value of 16 @ 4 $ 5 # 72 * 8 = 

Answer the questions based on the below information.

If '+' is 'x', '-' is '+', 'x' is '/' and '/' is '-' then 3 x 2 + 4 - 2 / 9 = ?