For the following questions

Find the odd word/letters/number pair from the given alternatives. 

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

6 : 42 :: 12 : ?

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

DBCE : QOPR :: JLKI : ?   

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

CURE : DISEASE :: HEAL : ? 

The total surface area of a sphere is 8p square unit. The volume of the sphere is

The diameters of two circles are the side of a square and the diagonal of the square. The ratio of the areas of the smaller circle and the larger circle is