Verbal Reasoning - Mental Ability Questions

In a certain code language, 'x' represents '+', '÷' represents 'x', '-' represents '÷' and '+' represents '-'. Find out the answer to the following question.

18 x 12 ÷ 5 - 10 + 10 = ?

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

50 + 3 ÷ 125 x 5 - 25 = ?

In the following question, select the related word pair from the given alternatives.
Canada : Ottawa : : ? : ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

130, 450, 970, 1690, ?

Water :Ocean :: Snow : ?

A series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series. 100, 50, 52, 26, 28, ? , 16, 8

In the following question, select the related number from the given alternatives.
9143 : 9963 : : 6731 : ?

If "+" means "minus", "x" means "divided by", "÷" means "plus" and "­" means "multiplied by", then 240 x 12 – 6 + 29 ÷ 42 = ?