At ________ the centigrade and Fahrenheit scales are

Some equations are solved based on a certain system. On the same basis find out the correct answer for the unsolved equation.  

Book : Author :: Furniture : ?

Based on the relationship between first two words, find out the missing word.

Amphibian: Frog ::   Terrestrial: ?

If 23 @ 18 = 9 and 29 @ 24 = 21', then 24 @ 19 = ?'. What will come in place of question mark?

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

7: 56 :: 5:?

If 18 & 6 # 32 = 76 and 60 # 6 & 5 = 10, then 15 & 5 # 42=?

If 60 [15] 3 and 108 [63] 7, then what is the value of A in 156 [A] 16?

Select the option that is related to the third term in the same way as the second term is related to the first term.

BSTN: AQUP :: DNUC : ?