Page 296 - Services Selection Board (SSB) Interviews

292 Logical Connectivity

Concept Cracker

1. (d) It is an example of either a or b type: 2 (d) It is an example of either a or b type:
Consider CB it implies – b → a that is logically CD a → –b that is logically incorrect.
correct. BA a → b that is also logically incorrect.
DA- it implies – a → b that is also logically correct. DB b → a that is also logically correct
AB it implies – a → –b that is logically incorrect. CA – a → b that is also logically correct
Hence both CB and DA are correct. 3. (a) Same as above AD is logically correct
4. (d) Same as above AB and CD are logically correct

Concept Deviator

1. (b( (H) Water level in the coast area does not rise Option B: If sprinklers do not start then the fire alarm
From (D) → Temperature will not rise doesn’t go off. Further we cannot say anything about
From (F) → People change their lifestyle the automatic alarm at the fire department.
From (B) → People will be rewarded, which is given Option C: When there is a fire the fire alarm goes off
in G. so sprinklers start. Hence an automatic alarm is set
2. (c) (G) → Vina dances off at the fire department.
From (E) → Kumar sings Option (D) is similarly ruled out.
From (B) → Audience dance 7. (d) Admission in one of the IIM’s ensures good
performance in CAT. This implies doing well in
From (C) → Concert will be successful, which is JMET. This ensures that you get into one of the IITS
given in H. or IISC So option D is true.
3. (b) The conclusion should be if Manisha ate the
orange, then Rajesh did not cook, 8. (b) Let X be the event that Geeta is present in the photo
4. (b) From first two statements we can conclude: ‘if and event Y that her sisters are present. Given that
X → Y.
the contract is valid then X would be bankrupt.’
Statement 3 is ‘If he goes bankrupt, then the bank As per the given information in the photo already
will not loan him the money.’ From above two has three people (Geeta’sparents with their son 3
statements, we have: If the contract is valid, then the persons so remaining can be only 2 persons). Thus,
bank will not loan him the money. This is reflected in Geeta cannot be in the photo.
option B. 9. (c) Here let X be the event that the student sees a
5. (d) Lets eliminate options one by one- teacher. And event Y be the event that he is sleeping.
Option A: Child is hungry. So, from (ii) child is We have been given that X → ~Y. However, we do
crying, but we cannot say anything about the child not know anything about ~ X, and the question asks
liking milk or not. us what Y will be if ~X.
Option B: A child is crying, but from this we cannot \ We cannot conclude anything.
say anything regarding the child being hungry or 10. (c) This is the situation of “Only if X then Y and Z” it
unhappy. implies that:
Option C: The statements are not speaking about (i) (Y and Z → X)
the happy child.
Option D: Unhappy children are hungry and (ii) (~ X → ~ Y or/and ~ Z) given in option (C)
hungry children cry. So choice (D) is most logically 11. (c) This is the situation of “If X then Y and Z” it
supported. implies that:
6. (c) Lets eliminate options one by one- (i) (X → Y and Z)
Option A: Cannot be true since we cannot infer (ii) (~ Y or/and ~Z → ~X) given in option (C)
anything if we know that an automatic alarm is set
off at the fire department.