Verbal Reasoning - Mental Ability Questions

Select the related word/letters/numbers from the given alternatives:
3 : 243 :: 5 : ?

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?

45 x 5 + 2 - 20 = ?

In the following question, select the related letter pair from the given alternatives.PIR : OHQ : : ? : ?

In a row, there are 8 girls between Aruna and Bimla and Aruna being the first girl in row. There are 5 girls between Bimla and Chetna. If there are 14 girls after Chetna, then how many minimum girls are there in the row?

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?
25 + 10 ÷ 240 x 16 = ?

P is the brother of Q. Q is the brother of R. P is the son of S. Based these three statements, much of the following statements cannot be definitely true?

Ram said , "Sita is my paternal great grandfather's only son's only daughter-in-law". How is Sita related to Ram?

If + means division, ­ means multiplication, '÷' means subtraction, x means addition, and < means less than, then which of the following is false?