Verbal Reasoning - Mental Ability Questions

Select the number which can be placed at the place of ? in the following question

If 18α12 = 3, 2α14 = -6 and 4α4 = 0, then find the value of 2α16 = ?

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

7 x 10 ÷ 30 - 2 + 6 = ?

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

2 ÷ 12 - 6 + 20 x 4 = ?

In each of the questions below are given three statements followed by three conclusions numbered I, II, and III. You have to take the given statements to be true even if they seem to be at variance with commonly known facts. Read all the conclusions and then decide which of the given conclusions logically follow(s) from the given statements disregarding commonly known facts.
Statements:
Some tables are chairs.
All chairs are benches.
All benches are desks.
Conclusions:
I. Some desks are tables.
II. Some benches are tables.
III. Some desks are chairs.

MATHEMATICS is related to NUMBERS in the same way HISTORY is related to

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

CAP, AXL, YUH, WRD, ?

The weights of 4 boxes are 30, 20, 50 and 90 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxes and in a combination a box can be used only once?