Reasoning Ability
Blood Relation Gender Fix — "A's son's wife" is always A's daughter-in-law (female); "mother's brother" is always maternal uncle. Draw quick stick figures with M/F labels to avoid pronoun confusion traps.
Coding +13 Pattern — If A→N, B→O (each letter +13), it's ROT13 cipher. Quick check: apply twice returns original. Common in letter-shift coding questions.
Clockwise NESW — Directions rotate clockwise: North→East→South→West. Right turn = +1 step clockwise, Left = -1 step. Count net turns to find final direction fast.
Odd-One-Out by Properties — Check in order: divisibility (prime vs composite), digit count, perfect squares/cubes, vowel/consonant pattern. Systematic scan beats random guessing.
Series: Difference of Differences — For number series, write first differences below, then second differences. Pattern often appears in second/third level (constant or arithmetic).
General Awareness
Delhi NCT: 1991, 1992, 1993 — NCT status (1991), Article 239AA inserted (1991), Sheila Dikshit became CM (1998—memory anchor). Separate 1991 as constitutional milestone.
Delhi Capitals Mnemonic — Old capitals: Indraprastha (Pandavas), Lal Kot (Prithviraj), Siri (Alauddin), Tughlaqabad (Tughlaq), Shahjahanabad (Shah Jahan). Remember "I Love Saturday Totally, Sunday" for chronology.
Freedom Struggle Dates — 1857 (Revolt), 1885 (Congress), 1905 (Bengal Partition), 1919 (Jallianwala), 1930 (Salt), 1942 (Quit India). Anchor: "57-85-05-19-30-42" (odd-even pattern helps).
Environment Days — World Environment Day (June 5 = 5/6), Earth Day (April 22 = 4/22). Remember: "5-6 for trees, 4-22 for Earth" (rhyme-number link).
Indian Neighbours Clockwise — From northwest clockwise: Pakistan, China, Nepal, Bhutan, Bangladesh, Myanmar. Mnemonic: "Please Call Nina Before Bad Morning" for borders clockwise from J&K.
Quantitative Aptitude
Divisibility by 11 — Alternating digit sum: (sum odd positions) − (sum even positions) divisible by 11. Example: 1221 → (1+2)−(2+1)=0, divisible.
Time-Distance: Relative Speed — Same direction: subtract speeds. Opposite: add speeds. Circular track meeting: distance/sum of speeds for opposite; distance/difference for same direction.
Profit % Fast Formula — If CP=100, SP=120, Profit=20%. Direct: Profit% = [(SP−CP)/CP]×100. Reverse: CP = SP×100/(100+Profit%).
SI vs CI Difference (2 years) — For 2 years, CI−SI = P(R/100)². Easy calculator: if P=10,000 and R=10%, difference=10,000×(0.1)²=₹100.
Average Addition Trick — If n numbers average A, total=n×A. Add one number x: new average = (n×A + x)/(n+1). Drop one: (n×A − x)/(n−1).
Percentage-Fraction Anchors — Memorize: 12.5%=1/8, 16.67%=1/6, 33.33%=1/3, 37.5%=3/8, 62.5%=5/8, 66.67%=2/3. Convert instantly to simplify calculations.
Geometry: Triangle Area Shortcut — Heron's formula when sides given: s=(a+b+c)/2, Area=√[s(s−a)(s−b)(s−c)]. For right triangle, just (1/2)×base×height.
Ratio Mixing (Alligation) — To mix two items at prices P1, P2 to get mean price M: ratio = (M−P2):(P1−M). Draw X-diagram: cheaper and dearer crosswise.
Computer Knowledge
OSI Layers Mnemonic — "All People Seem To Need Data Processing" = Application, Presentation, Session, Transport, Network, Data Link, Physical (7 layers top-down).
Storage Size Ladder — Bit < Nibble (4 bits) < Byte (8 bits) < KB (1024 B) < MB < GB < TB. Remember: 1 KB = 1024 bytes (not 1000).
Email Protocol Trio — SMTP sends (port 25), POP3 downloads-deletes (port 110), IMAP syncs-keeps on server (port 143). "Send Picks Inbox" for function order.
MS Excel: Function Starters — SUM, AVERAGE, MAX, MIN, COUNT, IF start with "=". Example: =SUM(A1:A10). COUNTIF, SUMIF add conditions; VLOOKUP for vertical lookups.
Shortcut Keys Core — Ctrl+C (copy), Ctrl+V (paste), Ctrl+X (cut), Ctrl+Z (undo), Ctrl+S (save), Ctrl+P (print). Alt+F4 closes window; Win+D shows desktop.