Bihar School Librarian Eligibility Test: Reasoning Study Notes and Question Bank

A comprehensive, exam-oriented study guide covering foundational reasoning sections tested in the Bihar School Librarian examination. This guide analyzes question patterns, step-by-step logic, standardized problem templates, and practical deduction strategies across Coding-Decoding, Blood Relations, Direction Sense, Series Completion, and Syllogism.

1. Letter-Based Coding-Decoding: Positional Shift Patterns

Letter-to-letter coding problems assess your ability to recognize consistent alphabetic displacement. In these patterns, every letter of a source word advances forward or backward by a uniform integer offset across the English alphabet (A = 1 to Z = 26).

Consider the progressive shifts featured in the exam bank using the base words 'ROSE' (18, 15, 19, 5) and 'MIND' (13, 9, 14, 4):

+1 Shift Pattern: If 'ROSE' is coded as 'SPTF' (R+1=S, O+1=P, S+1=T, E+1=F), then 'MIND' is coded by advancing each letter by one position: M+1=N, I+1=J, N+1=O, D+1=E, producing NJOE. Similarly, 'WATER' becomes 'XBUFS' (W+1=X, A+1=B, T+1=U, E+1=F, R+1=S), which encodes 'TIGER' as UJHFS (T+1=U, I+1=J, G+1=H, E+1=F, R+1=S).

+2 Shift Pattern: If 'ROSE' is coded as 'TQUG' (R+2=T, O+2=Q, S+2=U, E+2=G), applying a +2 shift to 'MIND' yields M+2=O, I+2=K, N+2=P, D+2=F, producing OKPF.

+3 Shift Pattern: If 'ROSE' is coded as 'URVH' (R+3=U, O+3=R, S+3=V, E+3=H), applying a +3 shift to 'MIND' gives M+3=P, I+3=L, N+3=Q, D+3=G, producing PLQG.

+4 Shift Pattern: If 'ROSE' is coded as 'VSWI' (R+4=V, O+4=S, S+4=W, E+4=I), shifting 'MIND' by +4 positions results in M+4=Q, I+4=M, N+4=R, D+4=H, yielding QMRH.

+5 Shift Pattern: If 'ROSE' is coded as 'WTXJ' (R+5=W, O+5=T, S+5=X, E+5=J), advancing 'MIND' by +5 steps gives M+5=R, I+5=N, N+5=S, D+5=I, resulting in RNSI.

2. Structural Coding: Letter Reversal and Positional Summation

In structural coding, words are either rearranged without shifting their alphabet values or converted into numerical totals based on their positional weights.

Reversal of Order: When 'TAP' is coded as 'PAT', and 'BAT' is coded as 'TAB', the coding rule reverses the entire sequence of characters. Applying this exact transformation to 'KIND' reverses the order from first-to-last into last-to-first: the letter in the 4th position (D) moves to 1st, 3rd (N) to 2nd, 2nd (I) to 3rd, and 1st (K) to 4th, yielding DNIK.

Positional Summation: If 'A' = 1 and 'BANANA' = 33, the underlying rule is the direct summation of the 1-indexed positional value of every letter. Verification: B(2) + A(1) + N(14) + A(1) + N(14) + A(1) = 33. To find the value of 'ORANGE', sum each letter's positional index: O = 15, R = 18, A = 1, N = 14, G = 7, E = 5. Calculating the total: 15 + 18 + 1 + 14 + 7 + 5 = 60.

3. Blood Relations: Kinship Deductions and Portrait Puzzles

Blood relation problems require breaking down indirect conversational descriptions into straightforward family tree linkages. The exam bank emphasizes three principal types of kinship relations:

Self-Referential Portrait Puzzle: "Pointing to a photograph, a man said: 'I have no brother or sister but that man's father is my father's son.' Whose photograph was it?" Analysis: Break the statement into components from the speaker's perspective. The speaker states he has no brothers or sisters (an only child). Therefore, 'my father's son' can only refer to the speaker himself. Substituting this back into the statement gives: 'That man's father is [the speaker]'. If the speaker is the father of the person in the photograph, the portrait belongs to his son.

Maternal and Paternal Indirect Introduction: "Introducing a girl, Vipin said: 'She is the daughter of the only sister of my father.' How is Vipin related to the girl?" Analysis: The only sister of Vipin's father is Vipin's paternal aunt (Bua). The daughter of one's paternal aunt is a first cousin. Thus, Vipin is the cousin of the girl.

Multi-Generation Kinship Chains: "If A is the brother of B, B is the sister of C, and C is the father of D, how is A related to D?" Analysis: A and B are siblings, and B and C are siblings; hence, A, B, and C are all siblings (with A being male, B female, and C male). Because C is the biological father of D, C's brother A is D's father's brother, formally designated as D's Paternal Uncle.

In-Law Relationships: "A and B are a married couple. X and Y are brothers. X is the brother of A. How is Y related to B?" Analysis: Since X and Y are brothers, and X is A's brother, Y must also be the brother of A. Because A is married to B, the brother of one's spouse is one's brother-in-law. Therefore, Y is the brother-in-law of B.

4. Direction Sense: Displacements, Cardinal Turns, and Shadows

Direction sense problems test an understanding of the cardinal compass (North, South, East, West), orthogonal turns, the Pythagorean distance theorem, and shadow projections based on solar position.

Multi-Turn Displacement: "A man walks 5 km South, turns right, walks 3 km, turns left, and walks 5 km. In which direction is he from the starting place?" Analysis: Walking South moves him down the vertical axis (-5y). Turning right while facing South directs him toward the West (-3x). Turning left while facing West directs him South again (-5y). His net coordinates relative to origin (0,0) are (-3, -10), placing him in the South-West quadrant from his starting position.

Solar Orientation Navigation: "Rahul started walking positioning his back towards the sun in the morning. After some time, he turned left, then turned right, and towards the left again. In which direction is he going now?" Analysis: In the morning, the sun is in the East. Walking with one's back to the morning sun means walking West. Facing West, a left turn directs him South. Facing South, a right turn directs him West. Facing West, turning left again directs him South. Note that if the problem allows for alternate interpretations where the time of day or direction could be inverted, the direction is North or South depending on whether the orientation started relative to the East or West.

Pythagorean Shortest Distance: "A man walks 6 km North, turns right and walks 8 km. How far is he from his starting point?" Analysis: The path forms a right-angled triangle where the legs are 6 km (North) and 8 km (East). Shortest straight-line displacement = √(6² + 8²) = √(36 + 64) = √100 = 10 km.

Morning Shadow Deduction: "One morning after sunrise, Suresh was standing facing a pole. The shadow of the pole fell exactly to his right. To which direction was he facing?" Analysis: Since the sun rises in the East, any object casts its shadow directly toward the West. The shadow of the pole falls to Suresh's right side, which means Suresh's right arm points West. If a person's right hand points West, their left hand points East, their back faces North, and they are facing South.

5. Series Completion: Number Patterns and Alphabet Progressions

Series completion tests the detection of arithmetic steps, multiplicative scaling, interleaved alternating patterns, or alphabetic positional skips.

Constant Difference Series (Arithmetic Progression): The question bank contains regular arithmetic sequences increasing by a uniform difference of +3: '122, 125, 128, 131, ...' Next term = 131 + 3 = 134; '130, 133, 136, 139, ...' Next term = 139 + 3 = 142; '138, 141, 144, 147, ...' Next term = 147 + 3 = 150; '146, 149, 152, 155, ...' Next term = 155 + 3 = 158; '154, 157, 160, 163, ...' Next term = 163 + 3 = 166.

Geometric Scaling Progression: '2, 4, 8, 16, 32, ...' Analysis: Every successive term is obtained by multiplying the previous term by a common ratio of 2 (2×2=4, 4×2=8, 8×2=16, 16×2=32). Next term = 32 × 2 = 64.

Dual Alternating Step Series: '7, 10, 8, 11, 9, 12, ...' Analysis: The series alternates between adding 3 and subtracting 2: 7 + 3 = 10; 10 - 2 = 8; 8 + 3 = 11; 11 - 2 = 9; 9 + 3 = 12. Following this alternating pattern, the next operation must be -2: 12 - 2 = 10.

Alphabet Gap Progression: 'B, D, F, H, J, ?' Analysis: Examining the alphabetical values: B = 2, D = 4, F = 6, H = 8, J = 10. The letters increment by +2 positions (skipping exactly one letter between them: C, E, G, I). The next value is 10 + 2 = 12, which corresponds to the letter L.

6. Syllogistic Deductions: Logical Quantifiers and Venn Analysis

Syllogism evaluates whether stated conclusions logically follow from given premises regardless of real-world facts. Valid deductions must hold true across all possible Euler/Venn diagram configurations.

Universal Affirmative Chaining: Statements: (I) All stones are bricks. (II) All bricks are trees. Conclusions: (1) All stones are trees. (2) Some trees are bricks. Analysis: Because the set of 'stones' is entirely contained inside the set of 'bricks', and 'bricks' is entirely contained inside 'trees', the set of 'stones' is inevitably inside 'trees'. Conclusion 1 is valid. Furthermore, because 'bricks' occupies a non-empty subset inside 'trees', some portion of 'trees' is definitely 'bricks'. Conclusion 2 is valid. Answer: Both 1 and 2 follow.

Particular Affirmative Overlap: Statements: (I) Some papers are pens. (II) All pens are pencils. Conclusions: (1) Some papers are pencils. (2) No pencil is a paper. Analysis: Since some papers are pens, and every pen is enclosed within the category of pencils, the intersection between papers and pens must also fall inside pencils. Therefore, 'Some papers are pencils' is necessarily true (Conclusion 1 follows). Conclusion 2 directly contradicts this established positive overlap and is false. Answer: Only 1 follows.

Independent Subsets in Common Super-category: Statements: (I) All cars are cats. (II) All fans are cats. Conclusions: (1) All cars are fans. (2) Some fans are cars. Analysis: Both 'cars' and 'fans' are distinct subsets placed within the broader set 'cats'. There is no stated relationship or necessary intersection connecting 'cars' and 'fans'. They may be completely disjoint circles within 'cats'. Neither conclusion follows with certainty. Answer: Neither 1 nor 2 follows.

Universal Negative with Universal Affirmative: Statements: (I) No window is a door. (II) All doors are walls. Conclusions: (1) Some walls are doors. (2) No wall is a window. Analysis: Because all doors are contained inside walls, the portion of walls that constitutes doors confirms that 'Some walls are doors' is definitively true (Conclusion 1 follows). However, while doors cannot touch windows, walls can be broader than doors and may overlap with windows. Thus, 'No wall is a window' cannot be proven with absolute certainty. Answer: Only 1 follows.

7. Quick-Reference Exam Tips for Bihar Librarian Aspirants

To maximize score efficiency in the 100-question reasoning segment of the Bihar Librarian examination, incorporate these proven test-taking strategies:

Pre-Draft the Alphabet Grid: At the start of the exam session, write down letters A to M (numbered 1 to 13) and directly beneath them N to Z in reverse (numbered 14 to 26). This instantly gives you both the direct forward ranks and opposite letter pairs (e.g., A-Z, B-Y, C-X, D-W), saving critical minutes on coding-decoding and letter series questions.

Syllogism Definite vs. Possibility Check: Never assume an intersection between two classes unless explicitly mandated by the statements. If two categories share an enclosing circle (like 'All cars are cats' and 'All fans are cats'), treat them as completely independent unless a statement explicitly bridges them.

Rapid Direction Tracking: Treat turns sequentially without turning your whole body or paper. When facing North, right is East and left is West; when facing South, right is West and left is East; when facing East, right is South and left is North; when facing West, right is North and left is South. Always recognize common Pythagorean triplets (3-4-5, 6-8-10, 5-12-13) for instantaneous distance calculations.