Verbal Reasoning - Mental Ability Questions

Each  of  the  following  questions has   four   statements.   Three   are   logically correct.  Some  of  which  may  look  factually absurd.  Ignore  this  absurdity  and  look  to  the logical   corrections.   Choose   the   statement which is wrong or doubtful:-

If 'x' means '-', '-' means 'x', '+' means '/' and '/' means '+', then what is the value of 15 - 2 / 900 + 90 x 100?

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

80 + 2 ÷ 25 + 5 - 10 = ?

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

bat, thin, reply, length, ?

If 19#13=3; 25#3=11; 36#10=13; then what is the value of 7#3=?

Two motorcyclists P and Q start from the same point. P rides 11 km West, then turns South and rides 16 km, then turns to his right and rides 14 km. Q rides 30 km South, then turns to his right and rides 25 km. Where is Q with respect to P now?

Arrange the given words in the sequence in which they occur in the dictionary.
i. Victory
ii. Victorious
iii. Vaccine
iv. Vacancy

Pointing at X, Y says, "X is the son of the only son of my mother". Then Y is X's ___.