Verbal Reasoning - Mental Ability Questions

Pointing to a photograph, a lady tells Pramod, "I am the only daughter of this lady and her son is your maternal uncle." How is the speaker related to Pramod's father 

Select the related word/letters/number from the given alternatives.

9 : 27 : : 64 : ?

Select the related word/letters/number from the given alternatives.

EF : UV : : IJ : ?

Answer the questions based on the below information.

If '+' is 'x', '-' is '+', 'x' is '/' and '/' is '-' then 6 + 7 x 3 - 8 / 20 = ?

Select the related word/letters/number from the given alternatives.

Gloomy : Dull : : Merciless : ?

Select the related word/letters/numbers from the given alternatives:

LAMP : IXJM :: FISH : ?

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

Select the related word/letters/number from the given alternatives.

72:90::156:?