FREE PREVIEW Week 1 4 lessons

Reasoning: Verbal Basics

Analogy, odd one out, number and letter series, coding-decoding, blood relations and direction sense. These quick-scoring topics appear in almost every SSC, railway and bank reasoning paper.

Lessons in this module

Analogy and Classification (Odd One Out)

Lesson • 5 quiz questions

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Number Series, Letter Series and Alphabet Tests

Lesson • 5 quiz questions

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Coding and Decoding

Lesson • 5 quiz questions

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Blood Relations and Direction Sense

Lesson • 5 quiz questions

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Lesson notes

1. Analogy and Classification (Odd One Out)

An analogy question gives a pair with a relation and asks you to find a second pair with the same relation. A classification question gives four items; three share a property and you must pick the odd one. Both test how fast you can spot a relation.

How to solve an analogy in steps

Step 1: Look at the first pair and say the relation in one short sentence, for example 'a pen is used to write'.
Step 2: Apply the same sentence to the second pair: 'a knife is used to ...' gives 'cut'.
Common word relations: tool and use (Pen : Write), worker and tool (Carpenter : Saw), animal and young one (Dog : Puppy), animal and home (Bee : Hive), country and capital, part and whole (Petal : Flower), opposite words.
Number analogies use square, cube, multiply, add or a mix. Example: 3 : 27 :: 5 : ? Here 27 = 3 cubed, so the answer is 5 cubed = 125.
Letter analogies use positions. Example: ACE : BDF :: KMO : ? Each letter moves 1 step forward (A to B, C to D, E to F), so KMO becomes LNP.
If two options seem to fit, make your sentence more exact. 'Doctor : Hospital' is 'works in', not just 'related to'.

How to solve classification (odd one out)

Step 1: Find what three items share: same group (fruits, planets), same property (prime numbers, perfect squares) or same letter gap.
Step 2: The item that breaks the common rule is the answer. Check that the other three really share it.
Word example: Mercury, Venus, Moon, Mars. Three are planets; Moon is a satellite, so Moon is odd.
Number example: 121, 169, 225, 200. The first three are perfect squares (11, 13 and 15 squared); 200 is not.
Letter-pair example: BD, FH, JL, MP. In the first three the gap is 2 (B to D skips C). M to P has a gap of 3, so MP is odd.

Shortcuts and common traps

Learn the alphabet positions: A1, E5, J10, O15, T20, Z26. The phrase 'EJOTY' (5, 10, 15, 20, 25) helps you find any letter fast.
Opposite letter pairs add up to 27: A-Z, B-Y, C-X, D-W, M-N. They are common in letter analogies.
Know squares up to 30 and cubes up to 15; they solve most number analogies in seconds.
Trap: picking an option that is related but in the wrong order. Keep the order of the first pair (cause : effect, worker : tool).
Trap: a surface feature can mislead. In 11, 13, 17, 21 all four are odd numbers, but 21 (3 x 7) is the only one that is not prime, so 21 is the odd one out.

Quick facts

A, E, J, O, T, Z: 1, 5, 10, 15, 20, 26
Opposite letters: positions add to 27
Bee : Hive: animal : home
Dog : Puppy: animal : young one
Pen : Write: tool : use

💡 Always say the relation as a full sentence before you look at the options. This stops you from choosing an option that only 'looks related'.

📝 5-question quiz on this lesson: enrol free to take it and track your score.

2. Number Series, Letter Series and Alphabet Tests

In a series question you get a list of numbers or letters that follow a rule. You must find the next term, a missing term or the wrong term. Most series use one of a few standard rules, so practice makes these very fast.

Method in steps

Step 1: Find the differences between neighbouring terms. If the differences are equal or follow a pattern, you have the rule.
Step 2: If differences grow very fast, try multiplication or division (x2, x3) or 'multiply then add/subtract'.
Step 3: Check squares and cubes (1, 4, 9, 16 ... or 1, 8, 27, 64 ...) and n x (n+1) (2, 6, 12, 20 ...).
Step 4: If nothing works, try two series mixed together: odd places follow one rule and even places another.
Step 5: Put your answer back in the series and check every term follows the same rule.

Worked examples

2, 6, 12, 20, 30, ? Differences are 4, 6, 8, 10, so the next difference is 12 and the answer is 42 (also 1x2, 2x3, 3x4 ... 6x7).
3, 5, 9, 17, 33, ? Each term is (previous x 2) - 1. So 33 x 2 - 1 = 65.
Wrong term: 4, 9, 16, 25, 35, 49. These are squares of 2 to 7, so 35 should be 36. The wrong term is 35.
Letter series: B, E, H, K, ? Each letter moves 3 steps forward (B2, E5, H8, K11), so the next is N (14).
Pair series: AZ, BY, CX, ? The first letter moves forward, the second moves back. Answer DW.

Alphabet position tests

'Which letter is 7th to the right of the 12th letter from the left?' Add: 12 + 7 = 19, and the 19th letter is S.
Position from the right end = 27 - position from the left. So the 5th letter from the right is the 22nd from the left, V.
'To the right' means add (move towards Z); 'to the left' means subtract (move towards A) when counting from the left end.
In series and coding questions a shift past Z normally goes round to A again (Y + 3 = B, using position 25 + 3 = 28 - 26 = 2).
Trap: in 'from the right' questions, people forget to convert positions. Always write the left position before adding or subtracting.

Quick facts

n x (n+1): 2, 6, 12, 20, 30, 42
Squares: 1, 4, 9, 16, 25, 36
Cubes: 1, 8, 27, 64, 125
Position from right: 27 - position from left
Primes: 2, 3, 5, 7, 11, 13, 17, 19, 23

💡 Write the differences under the series on your rough sheet. Nine out of ten series questions are solved at this first step.

📝 5-question quiz on this lesson: enrol free to take it and track your score.

3. Coding and Decoding

In coding-decoding a word, number or sentence is written in a secret form using a fixed rule. You find the rule from the given example and use it on a new word. The three main types are letter shift, substitution and sentence (new pattern) coding.

Letter-shift and position coding

Write the alphabet positions under each letter and compare the word with its code.
Example: CAT is written as DBU. C to D, A to B, T to U: each letter +1. So DOG becomes EPH.
Example: GOLD is written as FNKC (each letter -1). So SILVER becomes RHKUDQ.
Reverse coding: PENCIL is written as LICNEP (word written backwards). So MOBILE becomes ELIBOM.
Number coding: if BAD = 7, the rule may be the sum of positions (2 + 1 + 4). Then FACE = 6 + 1 + 3 + 5 = 15.
Some codes use opposite letters (A to Z, B to Y). Check this when +1 or -1 does not fit.

Substitution coding

Here one word is 'called' another word. Example: sky is called sea, sea is called water, water is called air, air is called cloud.
Question: where do fish live? Fish live in water, and water is called 'air'. So the answer is 'air'.
Step 1: Answer the question in real life. Step 2: Replace that real answer with its code name.
Trap: do not answer with the code of the word in the question. Answer with the code of the real answer.

Sentence coding (new pattern, bank style)

Example: 'la pe ro' means 'sweet hot tea', 'ro ki ma' means 'tea is ready', 'pe su ki' means 'hot is good'.
Compare sentences two at a time. 'tea' is common to the first two, and 'ro' is the common code, so ro = tea.
'is' is common to the 2nd and 3rd, so ki = is. 'hot' is common to the 1st and 3rd, so pe = hot.
The only word left in the first sentence is 'sweet', so la = sweet.
In this type the order of codes usually does not follow the order of words, so never match by position.

Quick facts

+1 shift: CAT to DBU
-1 shift: GOLD to FNKC
Reverse: PENCIL to LICNEP
Opposite letter: A-Z, B-Y, C-X
Sentence code: match common words with common codes

💡 For a new letter code, test the first two letters only. If the rule fits both, check the last letter, then apply it. This saves time.

📝 5-question quiz on this lesson: enrol free to take it and track your score.

4. Blood Relations and Direction Sense

Blood relation questions ask how two people are related. Direction questions ask where a person ends up or which way they face. Drawing a small diagram is the safest method for both.

Blood relations: method

Draw a family tree. Put elder generations at the top. Use + for male and - for female, a double line for husband-wife.
Break long sentences from the end. 'Son of my paternal grandfather's only son': my father's father's only son is my father; father's son is my brother (or the speaker himself, if the speaker is male).
Example: A is B's sister. C is B's mother. D is C's father. So D is the grandfather of A and B, and A (a girl) is D's granddaughter.
Know these: father's or mother's brother = uncle; brother's son = nephew; brother's daughter = niece; wife's brother = brother-in-law.
Coded type: 'A + B means A is the mother of B, A x B means A is the brother of B'. Decode each sign one step at a time.
Trap: gender is not always given. 'Child' or 'sibling' does not tell you male or female, so 'cannot be determined' may be correct.

Direction sense: method

Draw the four main directions: North up, South down, East right, West left. Between them are NE, NW, SE, SW.
Facing North, a right turn makes you face East and a left turn makes you face West. Facing South, a right turn makes you face West.
Clockwise 90 degrees = right turn. Anticlockwise 90 degrees = left turn. 180 degrees = facing the opposite way.
Example: walk 5 km North, turn right and walk 3 km, turn right and walk 5 km. You are now 3 km East of the start.
Shortest distance uses Pythagoras: 6 km East then 8 km North gives a distance of square root of (36 + 64) = 10 km.

Shadow questions and traps

In the morning the Sun is in the East, so shadows fall to the West. In the evening shadows fall to the East.
At noon (in India) the shadow is very short; such questions are rare.
Trap: 'turn left' depends on the direction the person is facing now, not on your page. Update the facing direction after every turn.
Trap: the question may ask direction of the start point from the end point, which is the opposite of the end point from the start point.

Quick facts

Facing N, turn right: East
Facing S, turn right: West
Clockwise 90°: right turn
Pythagoras triples: 3-4-5, 6-8-10, 5-12-13
Morning shadow: falls to the West

💡 Never solve direction or family questions in your head. A ten-second sketch avoids almost every mistake.

📝 5-question quiz on this lesson: enrol free to take it and track your score.

Other modules in Railway Exams Prep: RRB NTPC & Group D

Start Here: Railway Exams (RRB NTPC and Group D)FREE PREVIEW → Quantitative Aptitude: Number BasicsFREE PREVIEW → Quantitative Aptitude: Arithmetic IFREE PREVIEW → Quantitative Aptitude: Arithmetic IIFREE PREVIEW → Quantitative Aptitude: Advanced and DataFREE PREVIEW → Reasoning: Logic and ArrangementsFREE PREVIEW → Reasoning: Analytical and Non-VerbalFREE PREVIEW → General ScienceFREE PREVIEW → Environment and Ecology (Karnataka focus)FREE PREVIEW → Ancient IndiaFREE PREVIEW → Medieval IndiaFREE PREVIEW → Colonial Rule and the Freedom StruggleFREE PREVIEW → The Constitution of IndiaFREE PREVIEW → How India Is GovernedFREE PREVIEW → India's Economic Journey and PoliciesFREE PREVIEW → Indian Geography for National ExamsFREE PREVIEW → Static GK for National ExamsFREE PREVIEW → Computer KnowledgeFREE PREVIEW → Final AssessmentFREE PREVIEW →

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