Basic steps to solve Logical Puzzles
- Quickly read the question.
- Develop a general idea regarding the theme of the problem.
- Select the data that is giving you some concrete information out of total information given. Also, select the data which helps in ruling out certain possibilities.
- Useful secondary information: Generally, the first few sentences of the given data give you the basic information that is required to know the general idea of the problem. This is called the ‘useful secondary information’.
- Actual information: Data left after putting aside the useful secondary information is called actual information. While trying to solve the problem, you should begin with the actual information while the useful secondary information should be kept in mind.
- Negative Information: Some parts of the actual information may consist of negative information. Negative information does not inform us of anything exactly but it gives us a chance to eliminate a possibility. Sentences like “P is not the mother of Q” or “B is not a hill-station” are called negative information.
Additionally: draw a diagram to make it easier to visualise.
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1. A, B, C, D and E are sitting on a bench. A is sitting next to B, C is sitting next to D, D is not sitting with E who is on the left end of the bench. C is on the second position from the right. A is to the right of B and E. A and C are sitting together. In which position B is sitting?
a. Between C and D
b. Between C and A
c. Between E and D
d. Between E and A
2. A, B, C, D, E and F, not necessarily in that order, are sitting at a round table. A is between D and F, C is opposite to D and D and E are not on neighbouring chairs. Which one of the following pairs must be sitting on neighbouring chairs?
a. A and B
b. C and E
c. B and F
d. A and C
3. Seven men, A, B, C, D, E, F, and G are standing in a queue in that order. Each one wearing a cap of a different colours like violet, indigo, blue, green, yellow, orange and red. D is able to see in front of him green and blue, but not violet. E can see violet and yellow, but not red. G can see caps of all colours other than orange. If E is wearing an indigo-coloured cap, then the colour of the cap, worn by F is (UPSC 2013)
4. There are seven persons up on a ladder, A, B, C, D, E, F, and G (not in that order). A is further up than E but is lower than C. B is in the middl. G is between A and B. E is between B and F. If F is between E and D, the person on the bottom step of the ladder will be
5. Four children are sitting in a row. A is occupying the seat next to B but not next to C. If C is not sitting next to D, who is/are occupying seat/seats adjacent to D?
c. B and A
d. Impossible to tell
6. In five flats, one above the other, live five professionals. The professor has to go up to meet his IAS officer friend. The doctor is equally friendly to all, and has to go up as frequently as go down. The engineer has to go up to meet his MLA friend above whose flat lives the professor's friend. From the ground floor to the top floor, in what order do the five professionals live? (UPSC 2014)
a. Engineer, Professor, Doctor, IAS officer, MLA
b. Professor, Engineer, Doctor, IAS officer, MLA
c. IAS officer, Engineer, Doctor, Professor, MLA
d. Professor, Engineer, Doctor, MLA, IAS officer
7. Five people A, B, C, D and E are seated about a round table. Every chair is spaced equidistant from adjacent chairs. (UPSC 2013)
(i) C is seated next to A
(ii) A is seated two seats from D
(iii) B is not seated next to A
Which of the following must be true?
(I) D is seated next to B
(II) E is seated next to A
a. I only
b. II only
c. Both I and II
d. Neither I nor II
8. A group of 630 children is arranged in rows for a group photograph session. Each row contains three fewer children than the row in front of it. What number of rows is not possible?
9. Consider that: (UPSC 2014)
1. A is taller than B.
2. C is taller than A.
3. D is taller than C.
4. E is the tallest of all.
If they are made to sit in the above order of their height, who will occupy the mid position?
10. A society consists of only two types of people fighters and cowards. Two cowards are always friends. A fighter and a coward are always enemies. Fighters are indifferent to one another. If A and B are enemies, C and D are friends, E and F are indifferent to each other, A and E are not enemies, while Band F are enemies. (UPSC 2015)
Which of the following statements is correct?
a. B, C and F are cowards
b. A, E and F are fighters.
c. B and E are in the same category.
d. A and F are in different categories.
11. Two men Anil and David and two women Shabnam and Rekha are in a sales group. Only two speak Tamil. The other two speak Marathi. Only one man and one woman can drive a car. Shabnam speaks Marathi. Anil speaks Tamil. Both Rekha and David can drive.
Which of the following statements is true? (UPSC 2015)
a. Both the Tamil speakers can drive a car
b. Both the Marathi speakers can drive a car
c. Both of those who can drive a car speak Marathi
d. One of those who can drive a car speaks Tamil
12. In a school, there were five teachers.
A and B were teaching Hindi and English.
C and D were teaching English and Geography.
D and A were teaching Mathematics and Hindi
E and B were teaching History and French. (UPSC 2017)
Who among the teachers was teaching maximum number of subjects?
13. If 2 boys and 2 girls are to be arranged in a row so that the girls are not next to each other, how many possible arrangements are there? (UPSC 2017)
14. There are five hobby clubs in a college viz. photography, yachting, chess, electronics and gardening. The gardening group meets every second day, the electronics group meets every third day, the chess group meets every fourth day, the yachting group meets every fifth day and the photography group meets every sixth day. How many times do all the five groups meets on the same day within 180 days? (UPSC 2016)
15. Four girls are sitting on a bench to be photographed. Shikha is to the left of Meena. Manju is to the right of Meena. Nita is between Meena and Manju. Who would be second from the left in the photograph?
16. In a March Past, seven persons are standing in a row. Q is standing left to R but right to P. O is standing right to N and left to P. Similarly, S is standing right to R and left to T. Find out who is standing in the middle.
17. If A runs less fast than B and B runs as fast but not faster than C; then as compared to A, C runs (UPSC 2015)
a. slower than A
b. faster than A
c. with same speed as A
d. Given data is not sufficient to determine
18. Each of A, B, C and D has Rs 100. A pays Rs 20 to B, who pays Rs 10 to C, who gets Rs 30 from D. In this context, which one of the following statements is not correct?
a. D is the poorest
b. C is the richest
c. B is richer than D
d. C has more than what A and D have together
19. In a group of persons travelling in a bus, 6 persons can speak Tamil, 15 can speak Hindi and 6 can speak Gujarati. In that group, none can speak any other language. If 2 persons in the group can speak two language and one person can speak all the three languages, then how many persons are there in the group? (UPSC 2015)
20. A person is standing on the first step from the bottom of a ladder. If he has to climb 4 more steps to reach exactly the middle step how many steps does the ladder have?