Verbal Reasoning - Mental Ability Questions

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

13 ÷ 18 - 5 + 10 x 2 = ?

From the given alternative words, select the word which cannot be formed using the letters of the given word:
ECCENTRICITY

If 879= 8, 625= 1, 586= 9, then 785 = ?

From the given alternative words , select the word which cannot be formed using the letters of the given word :

I N T E L L I G E N C E

Which set of letters when sequentially placed at the gaps in the given letter series shall complete it?

CD_E_DD_CD_E

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

OK, SN, WQ, AT, ?

From the given alternatives, select the word which CANNOT be formed using the letters of the given word.

Transaction

From the given alternative words, select the word which cannot be formed using the letters of the given word:

ENVIRONMENT