CAT 2021 Slot 1 · DILR · Set 3: Friends, Acquaintances and Strangers
The full set and all 6 questions (Q11–Q16) from CAT 2021 Slot 1, with answers and solutions.
Amudha, Bharatan, Chandran, Dhinesh, Ezhil, Fani and Gowtham are seven people in a town. Any pair of them could either be strangers, acquaintances, or friends. All relationships are mutual. For example, if Amudha is a friend of Bharatan, then Bharatan is also a friend of Amudha. Similarly, if Amudha is a stranger to Bharatan, then Bharatan is also a stranger to Amudha.
Partial information about the number of friends, acquaintances, and strangers of each of these people among them is given in the table below.
No. of Friends | No. of Acquaintances | No. of Strangers | |
Amudha | 1 | 4 | |
Bharatan | |||
Chandran | 1 | ||
Dhinesh | 2 | ||
Ezhil | 1 | ||
Fani | 1 | ||
Gowtham | 3 | 2 |
The following additional facts are also known.
1. Amudha, Bharatan, and Chandran are mutual strangers.
2. Amudha, Dhinesh, and Fani are Ezil's friends.
3. Chandran and Gowtham are friends.
4. Every friend of Amudha is an acquaintance of Bharatan, and every acquaintance of Bharatan is a friend of Amudha.
5. Every friend of Bharatan is an acquaintance of Amudha, and every acquaintance of Amudha is a friend of Bharatan.
Question 11 · Caselet DI
- ADhinesh, Ezhil and Fani
- BAmudha, Dhinesh and Fani
- CBharatan, Dhinesh and Ezhil
- DAmudha, Bharatan and Fani
Answer & solution
Answer: Option A
Solving the set
Step 1 – Amudha, Bharatan and Chandran are mutual strangers (fact 1). Amudha has 4 strangers, so besides Bharatan and Chandran she has 2 more strangers, 1 acquaintance and 1 friend (6 relations). Ezhil is her friend (fact 2).
Step 2 – Facts 4 and 5: Amudha's friends = Bharatan's acquaintances, and Amudha's acquaintances = Bharatan's friends. So Ezhil is Bharatan's acquaintance, and Bharatan has exactly one friend (Amudha's single acquaintance).
Step 3 – Chandran–Gowtham are friends (fact 3). Gowtham has 3 acquaintances and 2 strangers, so his only friend is Chandran. Fani has only one friend – Ezhil (fact 2). Ezhil has only one stranger.
Step 4 – Testing who can be Amudha's acquaintance (= Bharatan's friend) among Dhinesh, Fani and Gowtham: Fani's only friend is Ezhil and Gowtham's only friend is Chandran, so it must be Dhinesh. Then Amudha's strangers are Bharatan, Chandran, Fani, Gowtham, and the remaining relations follow from the counts in the table.
Person | Friends | Acquaintances | Strangers |
Amudha | Ezhil | Dhinesh | Bharatan, Chandran, Fani, Gowtham |
Bharatan | Dhinesh | Ezhil | Amudha, Chandran, Fani, Gowtham |
Chandran | Gowtham | Fani | Amudha, Bharatan, Dhinesh, Ezhil |
Dhinesh | Bharatan, Ezhil | Amudha, Gowtham | Chandran, Fani |
Ezhil | Amudha, Dhinesh, Fani | Bharatan, Gowtham | Chandran |
Fani | Ezhil | Chandran, Gowtham | Amudha, Bharatan, Dhinesh |
Gowtham | Chandran | Dhinesh, Ezhil, Fani | Amudha, Bharatan |
This question
From the relationship table, Gowtham's acquaintances are Dhinesh, Ezhil and Fani.
Hence, the answer is option 1.
Question 12 · Caselet DI
- A(Amudha, Gowtham) and (Ezhil, Fani)
- B(Bharatan, Chandran) and (Dhinesh, Ezhil)
- C(Chandran, Ezhil) and (Dhinesh, Gowtham)
- D(Bharatan, Ezhil) and (Fani, Gowtham)
Answer & solution
Answer: Option D
Solving the set
Step 1 – Amudha, Bharatan and Chandran are mutual strangers (fact 1). Amudha has 4 strangers, so besides Bharatan and Chandran she has 2 more strangers, 1 acquaintance and 1 friend (6 relations). Ezhil is her friend (fact 2).
Step 2 – Facts 4 and 5: Amudha's friends = Bharatan's acquaintances, and Amudha's acquaintances = Bharatan's friends. So Ezhil is Bharatan's acquaintance, and Bharatan has exactly one friend (Amudha's single acquaintance).
Step 3 – Chandran–Gowtham are friends (fact 3). Gowtham has 3 acquaintances and 2 strangers, so his only friend is Chandran. Fani has only one friend – Ezhil (fact 2). Ezhil has only one stranger.
Step 4 – Testing who can be Amudha's acquaintance (= Bharatan's friend) among Dhinesh, Fani and Gowtham: Fani's only friend is Ezhil and Gowtham's only friend is Chandran, so it must be Dhinesh. Then Amudha's strangers are Bharatan, Chandran, Fani, Gowtham, and the remaining relations follow from the counts in the table.
Person | Friends | Acquaintances | Strangers |
Amudha | Ezhil | Dhinesh | Bharatan, Chandran, Fani, Gowtham |
Bharatan | Dhinesh | Ezhil | Amudha, Chandran, Fani, Gowtham |
Chandran | Gowtham | Fani | Amudha, Bharatan, Dhinesh, Ezhil |
Dhinesh | Bharatan, Ezhil | Amudha, Gowtham | Chandran, Fani |
Ezhil | Amudha, Dhinesh, Fani | Bharatan, Gowtham | Chandran |
Fani | Ezhil | Chandran, Gowtham | Amudha, Bharatan, Dhinesh |
Gowtham | Chandran | Dhinesh, Ezhil, Fani | Amudha, Bharatan |
This question
• (Amudha, Gowtham) strangers vs (Ezhil, Fani) friends – different.
• (Bharatan, Chandran) strangers vs (Dhinesh, Ezhil) friends – different.
• (Chandran, Ezhil) strangers vs (Dhinesh, Gowtham) acquaintances – different.
• (Bharatan, Ezhil) acquaintances vs (Fani, Gowtham) acquaintances – same.
Hence, the answer is option 4.
Question 13 · Caselet DI
- ADhinesh
- BFani
- CGowtham
- DEzhil
Answer & solution
Answer: Option A
Solving the set
Step 1 – Amudha, Bharatan and Chandran are mutual strangers (fact 1). Amudha has 4 strangers, so besides Bharatan and Chandran she has 2 more strangers, 1 acquaintance and 1 friend (6 relations). Ezhil is her friend (fact 2).
Step 2 – Facts 4 and 5: Amudha's friends = Bharatan's acquaintances, and Amudha's acquaintances = Bharatan's friends. So Ezhil is Bharatan's acquaintance, and Bharatan has exactly one friend (Amudha's single acquaintance).
Step 3 – Chandran–Gowtham are friends (fact 3). Gowtham has 3 acquaintances and 2 strangers, so his only friend is Chandran. Fani has only one friend – Ezhil (fact 2). Ezhil has only one stranger.
Step 4 – Testing who can be Amudha's acquaintance (= Bharatan's friend) among Dhinesh, Fani and Gowtham: Fani's only friend is Ezhil and Gowtham's only friend is Chandran, so it must be Dhinesh. Then Amudha's strangers are Bharatan, Chandran, Fani, Gowtham, and the remaining relations follow from the counts in the table.
Person | Friends | Acquaintances | Strangers |
Amudha | Ezhil | Dhinesh | Bharatan, Chandran, Fani, Gowtham |
Bharatan | Dhinesh | Ezhil | Amudha, Chandran, Fani, Gowtham |
Chandran | Gowtham | Fani | Amudha, Bharatan, Dhinesh, Ezhil |
Dhinesh | Bharatan, Ezhil | Amudha, Gowtham | Chandran, Fani |
Ezhil | Amudha, Dhinesh, Fani | Bharatan, Gowtham | Chandran |
Fani | Ezhil | Chandran, Gowtham | Amudha, Bharatan, Dhinesh |
Gowtham | Chandran | Dhinesh, Ezhil, Fani | Amudha, Bharatan |
This question
From Step 4, Amudha's acquaintance is Dhinesh.
Hence, the answer is option 1.
Question 14 · Caselet DI
- ADhinesh
- BFani
- CEzhil
- DBharatan
Answer & solution
Answer: Option B
Solving the set
Step 1 – Amudha, Bharatan and Chandran are mutual strangers (fact 1). Amudha has 4 strangers, so besides Bharatan and Chandran she has 2 more strangers, 1 acquaintance and 1 friend (6 relations). Ezhil is her friend (fact 2).
Step 2 – Facts 4 and 5: Amudha's friends = Bharatan's acquaintances, and Amudha's acquaintances = Bharatan's friends. So Ezhil is Bharatan's acquaintance, and Bharatan has exactly one friend (Amudha's single acquaintance).
Step 3 – Chandran–Gowtham are friends (fact 3). Gowtham has 3 acquaintances and 2 strangers, so his only friend is Chandran. Fani has only one friend – Ezhil (fact 2). Ezhil has only one stranger.
Step 4 – Testing who can be Amudha's acquaintance (= Bharatan's friend) among Dhinesh, Fani and Gowtham: Fani's only friend is Ezhil and Gowtham's only friend is Chandran, so it must be Dhinesh. Then Amudha's strangers are Bharatan, Chandran, Fani, Gowtham, and the remaining relations follow from the counts in the table.
Person | Friends | Acquaintances | Strangers |
Amudha | Ezhil | Dhinesh | Bharatan, Chandran, Fani, Gowtham |
Bharatan | Dhinesh | Ezhil | Amudha, Chandran, Fani, Gowtham |
Chandran | Gowtham | Fani | Amudha, Bharatan, Dhinesh, Ezhil |
Dhinesh | Bharatan, Ezhil | Amudha, Gowtham | Chandran, Fani |
Ezhil | Amudha, Dhinesh, Fani | Bharatan, Gowtham | Chandran |
Fani | Ezhil | Chandran, Gowtham | Amudha, Bharatan, Dhinesh |
Gowtham | Chandran | Dhinesh, Ezhil, Fani | Amudha, Bharatan |
This question
From the relationship table, Chandran's acquaintance is Fani.
Hence, the answer is option 2.
Question 15 · Caselet DI
Answer & solution
Answer: 3
Solving the set
Step 1 – Amudha, Bharatan and Chandran are mutual strangers (fact 1). Amudha has 4 strangers, so besides Bharatan and Chandran she has 2 more strangers, 1 acquaintance and 1 friend (6 relations). Ezhil is her friend (fact 2).
Step 2 – Facts 4 and 5: Amudha's friends = Bharatan's acquaintances, and Amudha's acquaintances = Bharatan's friends. So Ezhil is Bharatan's acquaintance, and Bharatan has exactly one friend (Amudha's single acquaintance).
Step 3 – Chandran–Gowtham are friends (fact 3). Gowtham has 3 acquaintances and 2 strangers, so his only friend is Chandran. Fani has only one friend – Ezhil (fact 2). Ezhil has only one stranger.
Step 4 – Testing who can be Amudha's acquaintance (= Bharatan's friend) among Dhinesh, Fani and Gowtham: Fani's only friend is Ezhil and Gowtham's only friend is Chandran, so it must be Dhinesh. Then Amudha's strangers are Bharatan, Chandran, Fani, Gowtham, and the remaining relations follow from the counts in the table.
Person | Friends | Acquaintances | Strangers |
Amudha | Ezhil | Dhinesh | Bharatan, Chandran, Fani, Gowtham |
Bharatan | Dhinesh | Ezhil | Amudha, Chandran, Fani, Gowtham |
Chandran | Gowtham | Fani | Amudha, Bharatan, Dhinesh, Ezhil |
Dhinesh | Bharatan, Ezhil | Amudha, Gowtham | Chandran, Fani |
Ezhil | Amudha, Dhinesh, Fani | Bharatan, Gowtham | Chandran |
Fani | Ezhil | Chandran, Gowtham | Amudha, Bharatan, Dhinesh |
Gowtham | Chandran | Dhinesh, Ezhil, Fani | Amudha, Bharatan |
This question
Ezhil's friends are Amudha, Dhinesh and Fani – 3 friends.
Hence, the answer is 3.
Question 16 · Caselet DI
Answer & solution
Answer: 4
Solving the set
Step 1 – Amudha, Bharatan and Chandran are mutual strangers (fact 1). Amudha has 4 strangers, so besides Bharatan and Chandran she has 2 more strangers, 1 acquaintance and 1 friend (6 relations). Ezhil is her friend (fact 2).
Step 2 – Facts 4 and 5: Amudha's friends = Bharatan's acquaintances, and Amudha's acquaintances = Bharatan's friends. So Ezhil is Bharatan's acquaintance, and Bharatan has exactly one friend (Amudha's single acquaintance).
Step 3 – Chandran–Gowtham are friends (fact 3). Gowtham has 3 acquaintances and 2 strangers, so his only friend is Chandran. Fani has only one friend – Ezhil (fact 2). Ezhil has only one stranger.
Step 4 – Testing who can be Amudha's acquaintance (= Bharatan's friend) among Dhinesh, Fani and Gowtham: Fani's only friend is Ezhil and Gowtham's only friend is Chandran, so it must be Dhinesh. Then Amudha's strangers are Bharatan, Chandran, Fani, Gowtham, and the remaining relations follow from the counts in the table.
Person | Friends | Acquaintances | Strangers |
Amudha | Ezhil | Dhinesh | Bharatan, Chandran, Fani, Gowtham |
Bharatan | Dhinesh | Ezhil | Amudha, Chandran, Fani, Gowtham |
Chandran | Gowtham | Fani | Amudha, Bharatan, Dhinesh, Ezhil |
Dhinesh | Bharatan, Ezhil | Amudha, Gowtham | Chandran, Fani |
Ezhil | Amudha, Dhinesh, Fani | Bharatan, Gowtham | Chandran |
Fani | Ezhil | Chandran, Gowtham | Amudha, Bharatan, Dhinesh |
Gowtham | Chandran | Dhinesh, Ezhil, Fani | Amudha, Bharatan |
This question
Friends of Ezhil: Amudha, Dhinesh, Fani. Friends of these (excluding Ezhil): Amudha – none else; Dhinesh – Bharatan; Fani – none else. People who are a friend or friend-of-a-friend: Amudha, Dhinesh, Fani, Bharatan = 4.
Hence, the answer is 4.
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