Logical Analysis and Reasoning
Blood Relations — Parental Gender Trick — Mother's/Father's side: "Sister" becomes Aunt; "Brother" becomes Uncle. Maternal = Mother's side (both start with M); Paternal = Father's side (both start with consonant cluster). Simplifies extended-family questions instantly.
Direction Sense — NESW Clockwise Rule — Draw a + sign: North top, moving clockwise = N→E→S→W. Right turn = next direction clockwise; Left turn = anti-clockwise. 180° = opposite direction. Solves turn-based questions in 5 seconds.
Coding-Decoding — Alphabet Position Values — A=1, B=2...Z=26. Remember: E=5, J=10, T=20 as anchors. For reverse: Z=1, A=26. Quick mental math: M(13) is middle; split alphabet there for faster calculation.
Series — Difference Pattern Check — Write differences between consecutive terms. If differences form AP/GP/squares, you've found the pattern. Example: 3,5,9,17,33 → differences are 2,4,8,16 (powers of 2).
Syllogism — Venn Circle Method — "All A are B" = small A-circle inside big B-circle. "Some A are B" = overlapping circles. "No A are B" = separate circles. Draw before attempting; visual truth emerges immediately.
Seating Arrangement — Anchor Person First — Identify the person with most conditions stated. Place them first (fix position), then arrange others relative to this anchor. Circular: mark one seat as "reference North" to avoid confusion.
Numerical Analysis and Aptitude
Divisibility — Quick 3 and 9 Rule — Sum all digits. If sum divisible by 3, number divisible by 3. If sum divisible by 9, number divisible by 9. Example: 12345 → 1+2+3+4+5=15 → divisible by 3 only.
Percentage-Fraction Equivalents — Memorize: 12.5%=1/8, 16.67%=1/6, 20%=1/5, 25%=1/4, 33.33%=1/3, 50%=1/2, 66.67%=2/3. Instant conversion saves 15-20 seconds per percentage calculation in exam pressure.
Profit/Loss — Cost Price Recovery — SP = CP(100±Profit%)/100. Quick reverse: If SP and profit% given, CP = SP×100/(100+profit%). For loss, use (100−loss%). Remember: marked price ≠ selling price after discount.
Time-Speed-Distance — Relative Speed — Same direction: subtract speeds. Opposite direction: add speeds. Trains/objects crossing: add lengths. Distance = Speed × Time; lock this triangle (cover one, multiply/divide other two).
Simple Interest Fast Formula — SI = PRT/100. For "at what rate" questions: R = 100×SI/(P×T). When principal doubles: time = 100/rate. Triple: time = 200/rate. These shortcuts cut calculation time by half.
Ratio Mixing — Alligation Method — For two mixtures with different ratios/percentages, use cross-subtraction. Draw X-diagram: mean in center, given values at top corners, differences at bottom = required ratio. Works for mixtures, prices, concentrations.