General Studies
Five-Year Plan Recall — Odd plans (1st, 3rd, 5th) focused on agriculture/primary sector; Even plans (2nd, 4th) emphasized industry. Quick memory aid: O for Odd = O for Origin (agriculture).
Biodiversity Hotspots (India) — WEEHH: Western Ghats, Eastern Himalayas, Eastern Ghats, Himalayas (Northwest), Himalayas. India has 4 recognized hotspots; this mnemonic captures the core zones.
Ecological Pyramid Direction — "Energy Never Inverts" — energy pyramids always upright (never inverted), but number/biomass pyramids can invert in aquatic/forest ecosystems.
Poverty Line Methods — TDE: Tendulkar (2011), Drèze baseline, Expert group (Rangarajan 2014). Remember Tendulkar lowered urban poverty estimates vs. Rangarajan raised them.
GDP vs GNP Quick — GDP = Domestic Production (where); GNP = National People (who). Add NRI income to GDP for GNP; subtract foreign company profits from GDP.
Monsoon Onset Sequence — "Kids Always Make Dosas" — Kerala (Jun 1), Andaman (May 20), Mumbai (Jun 10), Delhi (Jun 29). Andaman gets it first in India actually.
Climate Change Protocols Timeline — "Kids Really Play" — Kyoto (1997), Rio Summit (1992 actually, so chronologically Rio-Kyoto-Paris), Paris (2015). Rio→Kyoto→Paris for major climate agreements.
Meghalaya — History, Culture, Geography & Administration
Three Hills of Meghalaya — "KJG" or "JKG": Jaintia Hills, Khasi Hills, Garo Hills. These are the three primary hill ranges forming Meghalaya's geography.
Wettest Places Order — "My Mom Cares" — Mawsynram (highest annual), Meghalaya state, Cherrapunji (second highest). Mawsynram beats Cherrapunji by ~100mm annually.
Major Rivers Mnemonic — "Just Keep Moving Slowly": Jaintia (Myntdu), Khasi (Umiam/Barapani), Myntang, Simsang (Garo Hills). Covers key rivers across three hill regions.
Meghalaya Formation Date — 21-1-1972 (21st Jan): Think "21 guns salute for 1 new hill state in '72." Carved from Assam as full state after autonomous status.
Garo Matrilineal System — "Mother Knows Best" — property/surname passes through female line (Khasi and Garo tribes). Youngest daughter (not son) inherits ancestral property.
Nongkhnum Island Fact — Asia's largest river island in Meghalaya (on Kynshi River near Sohra). Remember: "Non-Majuli" — bigger than Brahmaputra's Majuli locally, Asia's biggest river island.
Mental Ability and Aptitude
Divisibility by 11 Shortcut — Alternating digit sum = (odd position sum) − (even position sum). If result is 0 or multiple of 11, number divides by 11. E.g., 121: (1+1)−2=0✓
Calendar Day Formula — Odd Days — Ordinary year = 1 odd day; leap = 2 odd days. Century years: only 400-multiples are leap. 1600,2000 leap; 1700,1800,1900 not.
Digit Sum Divisibility (3 & 9) — Sum all digits: if divisible by 3, number is; if by 9, number is. E.g., 12345: 1+2+3+4+5=15 (÷3 yes, ÷9 no).
Blood Relations Shortcut — Draw quick family tree symbols: ▲ male, ○ female, = marriage, | child. Trace path to solve "father's sister's daughter" questions under 15 seconds.
Direction Sense — Clockwise Rotation — NEWS clockwise: North→East (90° right), East→South, South→West, West→North. Each right turn = +90°; left turn = −90° from current direction.
Percentage-Fraction Quick Converts — 12.5%=1/8, 16.67%=1/6, 20%=1/5, 25%=1/4, 33.33%=1/3, 50%=1/2. Memorize these six to solve faster without calculator.