Page 288 - Services Selection Board (SSB) Interviews

Chapter
Chapter
21 Logical Connectivity

Section Level No. of Questions
Concept Applicator Very Easy 10

Concept Builder Easy 10
Concept Cracker Moderate 4

Concept Deviator Difficult 16

INTRODUCTION

Questions based on logical statements and logical connectives has a wide scope and questions related to these concepts
are very frequent in different aptitude test exams. These questions can be handled easily if basic funda is clear.
Logical connectives is a statement which states that an event depends on another event. The name ‘logical’ is derived
from the fact that the occurrence of the second event depends only on the occurrence or non-occurrence of the first
means these two statements are logically connected.
In these type of logical connectivity situations, we deal with statements that are essentially sentences in the English
language. However, in logic we are not interested about the factual correctness of the sentence. We have to only check
the logical ‘truthfulness the statements.
There are different types of questions we will see each type one by one
Type 1: “If X the Y” or “Y if X”or “When X then Y” or “Whenever X then Y”
This statement implies that:
(i) If event X has occurred then event Y has to occur. (X → Y)
(ii) If event Y has not occur then Even X has not occur. (~ Y → ~X)
(iii) If event Y has occurred then event X may or may not occur. (No definite conclusion)
Type 2: “Y only if X”

This statement implies that:
(i) If event Y has occurred then event X has to occur. (Y → X)
(ii) If event X has not occur then event Y has not occur. (~ X → ~ Y)
(iii) If event X has occurred then event Y may or may not occur. (No definite conclusion)
Type 3: “Unless X, Y”or “Y unless X” or “X otherwise Y”or “ Either X or Y”
This statement implies that:
(i) If event X has not occur then Even Y has to occur. (~ X → Y)
(ii) If event Y has not occur then Event X has to occur. (~ Y → X)
(iii) If event X has occurred then event Y may or may not occur. (No definite conclusion)
(iv) If event Y has occurred then event X may or may not occur. (No definite conclusion)