About Logical Problems
A logical problem of this kind gives several comparative clues about a group of people and asks you to work out some part of their order. Each clue is a single link between two people, so the work is to join the links into a chain and then read the answer off that chain.
What you need to understand
- Each clue is a link: one person stands above another in the trait being described.
- A chain of clues that reaches from one person to the next in an unbroken line fixes the order of everyone in it.
- If two people are never linked, directly or through a chain, nothing can be concluded about their relative order.
- A superlative question, such as who is tallest, always refers to one end of the chain.
- The direction of the chain matters: reading it backwards gives the opposite answer.
How to work through these questions
- List the people and draw an arrow from the greater to the lesser for each clue.
- Join the arrows into chains wherever two clues share a person.
- Identify the chain that contains the people named in the question.
- Read that chain from one end to the other and take the position you need.
- If the question asks about two people who are not in the same chain, the answer is that the relationship is undetermined.
Mistakes that cost marks
- Reading the chain in the wrong direction when the question asks for a superlative.
- Assuming two people are ordered when no chain connects them.
- Answering with the person standing next to the one asked about rather than the end of the chain.
- Losing track of a person who appears in more than one clue.
- Treating a clue that compares two isolated people as though it ordered the whole group.
Worked example
Amit is taller than Bela. Bela is taller than Chetan. Chetan is taller than Divya. Who is the shortest?
- Draw an arrow from the taller to the shorter for each clue.
- The three clues form one chain: Amit, then Bela, then Chetan, then Divya.
- The question asks for the shortest, which is the end of the chain where everyone else is above.
- Reading the chain from top to bottom, Divya is last, so Divya is the shortest.
Answer: Divya
Practice questions with answers
A few Logical Problems questions with the full solution shown, so you can see
how the method is applied before you attempt the timed set.
Question 1
Study the clues and answer the question.
Hari scored more than Esha
Esha scored more than Isha
Divya scored more than Hari
Lata scored more than Divya
Who is the highest score?
-
A
Lata
-
B
Divya
-
C
Hari
-
D
Esha
Answer: Option A — with explanation
The clues form one chain: Lata scored more than Divya scored more than Hari scored more than Esha scored more than Isha.
Reading it end to end, Lata is first and Isha is last, so Lata is the highest score.
Common mistakes
- picked the middle of the chain: Hari
- stopped one place short in the chain: Divya
- read the chain from the wrong end: Esha
Question 2
Study the clues and answer the question.
Chetan faster than Gita
Gita faster than Farhan
Farhan faster than Amit
Lata faster than Chetan
Who is exactly in the middle of the group?
-
A
Chetan
-
B
Gita
-
C
Lata
-
D
Farhan
Answer: Option B — with explanation
The clues form one chain: Lata faster than Chetan faster than Gita faster than Farhan faster than Amit.
There are five people, so the one in the middle is third in the chain, which is Gita.
Common mistakes
- picked the top of the chain instead of the middle: Lata
- stopped one place above the middle: Chetan
- stopped one place below the middle: Farhan
Question 3
Study the clues and answer the question.
Divya older than Isha
Chetan older than Hari
Isha older than Amit
Which person is definitely above Isha?
-
A
Hari
-
B
Chetan
-
C
Amit
-
D
Divya
Answer: Option D — with explanation
The clues Divya older than Isha and Isha older than Amit put Divya above Isha, and Amit below.
Chetan and Hari are only ranked against each other, so nothing is known about where they sit. Only Divya is definitely above Isha.
Common mistakes
- belongs to the other pair in the clues: Chetan
- belongs to the other pair in the clues: Hari
- is below in the chain, not above it: Amit
Question 4
Study the clues and answer the question.
Esha older than Chetan
Divya older than Farhan
Chetan older than Bela
Farhan older than Esha
Who is the oldest?
-
A
Farhan
-
B
Divya
-
C
Chetan
-
D
Esha
Answer: Option B — with explanation
The clues form one chain: Divya older than Farhan older than Esha older than Chetan older than Bela.
Reading it end to end, Divya is first and Bela is last, so Divya is the oldest.
Common mistakes
- read the chain from the wrong end: Chetan
- picked the middle of the chain: Esha
- stopped one place short in the chain: Farhan
Question 5
Study the clues and answer the question.
Gita faster than Esha
Kiran faster than Amit
Farhan faster than Gita
Amit faster than Farhan
Who is exactly in the middle of the group?
-
A
Kiran
-
B
Gita
-
C
Amit
-
D
Farhan
Answer: Option D — with explanation
The clues form one chain: Kiran faster than Amit faster than Farhan faster than Gita faster than Esha.
There are five people, so the one in the middle is third in the chain, which is Farhan.
Common mistakes
- stopped one place above the middle: Amit
- stopped one place below the middle: Gita
- picked the top of the chain instead of the middle: Kiran
Frequently asked questions
How do I solve a ranking puzzle?
Turn every clue into an arrow pointing from the greater to the lesser, then join the arrows into chains. Once the chain is drawn, the question is only about reading a position off it.
What if some people are never compared with each other?
Then their relative order is genuinely unknown, and a question asking about it would have no answer. Questions are written so that the people you are asked about always sit in the same chain.
How do I avoid reading the chain backwards?
Decide before you start which end means most and which means least, then state it to yourself. A question about the tallest wants the top of the chain, and a question about the shortest wants the bottom.
What if two clues contradict each other?
That cannot happen in a well-formed question. If your chain contains a loop, you have misread a clue, so go back to the clues rather than trusting the diagram.
Do these puzzles always have five people?
The number varies, but four or five is most common. The method is identical whatever the size of the group; only the length of the chain changes.