1. Number Series, Letter Series & Coding-Decoding
A number series question gives a sequence and asks for the next (or a missing) term. The recurring pattern families are: constant difference (arithmetic), constant ratio (geometric), difference-of-differences (quadratic-style growth), alternating operations (+3, ×2, +3, ×2...), and series built from squares/cubes/primes. The fastest approach is always to compute the difference (or ratio) between consecutive terms first — that single step reveals almost every pattern immediately.
Coding-decoding assigns each letter a substitute (often shifted by a fixed number of positions in the alphabet, or reversed) and asks you to apply the same rule to a new word. The reliable method is to write out the alphabet with position numbers (A=1...Z=26) on scratch paper once, then read off the shift directly rather than counting in your head each time.
If CAT is coded as DBU, find the code for DOG.
Step 1: find the shift per letter
C(3) -> D(4) shift +1
A(1) -> B(2) shift +1
T(20)-> U(21) shift +1
Step 2: the rule is "shift every letter forward by 1"
Step 3: apply to DOG
D(4)->E(5) O(15)->P(16) G(7)->H(8)
Answer: DOG -> EPHNever conclude a coding rule from a single letter's shift — confirm it holds for at least two letters in the given example before applying it to the new word, since some schemes use different shifts for vowels vs. consonants.
2. Arithmetic Reasoning
Arithmetic reasoning wraps ordinary percentage, ratio, average and time-speed-distance calculations inside a word problem, testing whether you can translate the words into the right equation before you even start calculating. The recurring failure mode is not the arithmetic itself but misreading what quantity is actually being asked for (e.g. confusing "increase in percentage" with "percentage of the new value").
A dependable method: underline the final question first, list the given quantities with their units, write one equation connecting them, then solve. For percentage-change problems specifically, always compute change relative to the original value unless the question explicitly says otherwise — this single rule prevents the most common calculation trap in this topic.
3. Puzzle-Solving: Seating, Blood Relations & Direction Sense
Seating arrangement puzzles (linear or circular) test whether you can hold multiple constraints in your head simultaneously — the reliable technique is to draw the seats as blank slots first, place the most specific/constrained clue immediately (e.g. "X sits at the leftmost end"), and only then work through the relative clues ("Y sits two seats to the right of X").
Blood-relation puzzles are solved fastest by drawing a small family tree diagram rather than tracking relationships in your head — one generation per row, with +/- symbols for gender if needed. Direction-sense problems (someone walks north, then turns right, then walks further) are solved by literally sketching the path on paper with compass directions marked, then reading the final position and distance directly off the sketch using the Pythagorean theorem when the path forms a right angle.
Draw it. Every seating, blood-relation or direction puzzle becomes dramatically easier and less error-prone the moment it's a diagram instead of a mental model — this is worth the 15 seconds it costs every single time.
4. Hands-on Exercise
Build a personal pattern-recognition drill set
Speed on this unit comes from pattern-recognition reps, not new theory — so build and time yourself on a small custom set.
Do this:
- Write 5 number series of your own (one each: arithmetic, geometric, alternating-operation, squares-based, difference-of-differences) and solve them cold the next day to check retention.
- Design one coding-decoding scheme (pick a shift or a reversal rule) and encode/decode 3 words with it.
- Write one seating-arrangement puzzle with 5 people and 4 clues, solve it by drawing slots, and time how long it takes you.
- Draw a 3-generation family tree and write 3 blood-relation questions based on it for a study partner (or yourself, a day later) to solve.
In the real exam, this unit's marks are won or lost on speed, not difficulty — time every attempt from day one so you have a real baseline to improve against.
5. Exam-Style Practice (UGC NET Pattern)
Five NTA-pattern quantitative/logical reasoning questions with full worked solutions.
Q1
Find the next number in the series: 2, 6, 12, 20, 30, ?
A) 36
B) 40
C) 42
D) 45
Find the next number in the series: 2, 6, 12, 20, 30, ?
A) 36
B) 40
C) 42
D) 45
Correct answer: C) 42. The differences between consecutive terms are 4, 6, 8, 10 — increasing by 2 each time. The next difference is 12, so 30 + 12 = 42.
Q2
If in a certain code, GARDEN is written as HBSEFO, how is FLOWER written in the same code?
A) GMPXFS
B) EMPXFS
C) GMPYFS
D) GMPXFT
If in a certain code, GARDEN is written as HBSEFO, how is FLOWER written in the same code?
A) GMPXFS
B) EMPXFS
C) GMPYFS
D) GMPXFT
Correct answer: A) GMPXFS. Each letter in GARDEN is shifted forward by exactly 1 (G→H, A→B, R→S, D→E, E→F, N→O), so applying the same +1 shift to FLOWER gives F→G, L→M, O→P, W→X, E→F, R→S = GMPXFS.
Q3
A shopkeeper marks up an item's price by 25% and then offers a 20% discount on the marked price. What is the net effect on the original price?
A) No change
B) 5% increase
C) 5% decrease
D) 10% decrease
A shopkeeper marks up an item's price by 25% and then offers a 20% discount on the marked price. What is the net effect on the original price?
A) No change
B) 5% increase
C) 5% decrease
D) 10% decrease
Correct answer: A) No change. Taking the original price as 100: the marked price is 125, and a 20% discount on 125 is 25, leaving a final selling price of 100 — exactly the original price. In general, a +25% markup followed by a −20% discount always cancels out, since the net multiplier is 1.25 × 0.80 = 1.00.
Q4
Pointing to a photograph, Rima said, "He is the son of my grandfather's only child." How is the man in the photograph related to Rima?
A) Father
B) Brother
C) Uncle
D) Cousin
Pointing to a photograph, Rima said, "He is the son of my grandfather's only child." How is the man in the photograph related to Rima?
A) Father
B) Brother
C) Uncle
D) Cousin
Correct answer: B) Brother. Rima's grandfather's only child is Rima's own parent (mother or father). The son of Rima's parent is Rima's brother.
Q5
Rahul walks 5 km north, turns right and walks 3 km, then turns right again and walks 5 km. How far is he from his starting point, and in which direction?
A) 3 km, East
B) 3 km, West
C) 8 km, South
D) 3 km, North
Rahul walks 5 km north, turns right and walks 3 km, then turns right again and walks 5 km. How far is he from his starting point, and in which direction?
A) 3 km, East
B) 3 km, West
C) 8 km, South
D) 3 km, North
Correct answer: A) 3 km, East. Walking north 5 km, then right (east) 3 km, then right again (south) 5 km returns him to the same latitude as the start, but 3 km east of it — so he ends up 3 km due east of the starting point.