Data Interpretation & Logical Reasoning (General Prep) Exam Survival Guide

Window: CAT/GRE/GMAT/CUET/BITSAT/Bank PO etc.
Components: DI (tables/graphs/mixtures) • LR (arrangements/grids/sets/constraints)

Must-do topics (80/20 focus)

Data Interpretation

• Tables, bar/line/pie, combo & stacked charts; multi-axis graphs
• Ratios, % change vs percentage points, contribution share, CAGR
• Averages/weighted means; mixture/alligation in DI clothing
• Speed: difference, ratio, growth questions; unit/scale conversions
• DI reasoning: “rate vs count,” per-capita, normalization

Logical Reasoning

• Ordering/Sequencing (with/without positions, circular)
• Arrangements & Distributions (people → slots; items → boxes)
• Grids/Matrix (who–what–when) with binary clues
• Constraints with conditions (if/only if, either–or, at least/at most)
• Set/Venn (2/3 sets, inclusion–exclusion), team selection
• Syllogisms/Conditional logic (→, ↔, contrapositive), truth-liar mixes

Top traps (avoid)

• Reading a chart without TAUSL: Title • Axes • Units • Scale • Legend
• Comparing rates to totals (wrong base), or mixing % change with pp (percentage-point) change
• Treating stacked charts as independent series; ignoring negatives on axes
• Averaging percentages without weights; alligation cross done on the wrong quantities
• LR: guessing before a consistent diagram; missing “exactly one” vs “at least one”
• Overlooking mutual exclusivity vs independence in set/prob hybrids
• Not marking impossible slots → repeated backtracks

Time split (tune to exam)

• DI 50–60% (calc + reasoning)
• LR 40–50% (diagram + deduction)
  Two-pass method:

1. Harvest clean sets (1–2 min skim each).
2. Commit to 2–3 sets with best ROI.
3. One revisit pass for marked Qs only.

Last-48h checklist (do exactly this)

• Daily (90–120 min):
  • 2 DI sets tables/line/pie (mixed scales)
  • 1 stacked/combo chart set (multi-axis)
  • 1 LR arrangement/sequence + 1 grid/matrix
• Flash ring (1 page): TAUSL · % vs pp · CAGR formula · weighted mean · inclusion–exclusion · logic symbols & contrapositive
• Speed drills (10–12 min): 30 tiny calcs: mental ratios, % of, Δ% chain, quick averages
• Error log by tag: (Scale/Units, Base, Weighting, Diagram, Constraint)

Quick facts & frames (carry card)

DI mini-toolkit

• TAUSL: Title • Axes • Units • Scale • Legend → say the scale aloud
• % change: new−oldold×100%\frac{\text{new−old}}{\text{old}}\times100\%oldnew−old​×100% ; pp change = new% − old%
• Weighted mean: xˉ=∑wixi∑wi\bar x=\frac{\sum w_ix_i}{\sum w_i}xˉ=∑wi​∑wi​xi​​
• Alligation (two sources): ratio of quantities === cross-difference of target from each value
• CAGR (n periods): CAGR=(finalinitial)1/n−1\text{CAGR}=(\frac{\text{final}}{\text{initial}})^{1/n}-1CAGR=(initialfinal​)1/n−1
• Per-capita normalization: divide by population/base before comparing
• Check units every operation (k → M; kg ↔ tonnes; ₹ ↔ $; year vs quarter)

LR mini-toolkit

• Diagram first, then deduce (never in head)
• Constraint codes:
  • If A then B: A→BA\to BA→B; contrapositive: ¬B→¬A\neg B \to \neg A¬B→¬A
  • Exactly one: (A∨B)(A \lor B)(A∨B) and ¬(A∧B)\neg(A \land B)¬(A∧B)
  • At most one: pairwise ¬(A∧B)\neg(A\land B)¬(A∧B) for all pairs
• Grid logic: mark ✓ (must), ✗ (cannot),? (unknown); propagate after each clue
• Ordering: anchor with extremes (first/last), then place neighbors
• Sets (3-set): ∣A∪B∪C∣=∑∣A∣−∑∣A∩B∣+∣A∩B∩C∣|A\cup B\cup C|=\sum|A|-\sum|A\cap B|+|A\cap B\cap C|∣A∪B∪C∣=∑∣A∣−∑∣A∩B∣+∣A∩B∩C∣

Speed tactics (during test)

DI

• Scan questions before crunching—compute only what’s asked
• Prefer ratios & comparisons over full numbers
• Bound answers: quick hi/lo to kill options
• Convert once (units/scale), then reuse across Qs
• For stacked charts: separate layers; consider contribution %

LR

• Build one clean base diagram; copy it for branches
• Use elimination by contradiction with small branches first
• Mark impossible slots aggressively (save future time)
• When stuck, switch view (timeline ↔ table; circle ↔ line)

Exam-day mini-plan

• 3-min warm-up: 10 mental %/ratio calcs + 1 tiny grid
• Pass 1: skim all sets (≤1–2 min each) → star 2 DI + 1 LR you like
• Pass 2: finish starred sets end-to-end; avoid set-hopping
• Final 8–10 min: revisit one marked Q per set; audit units/base/scale on DI, consistency on LR

Practice cycle (weekly)

1. Diagnose: 6 sets (3 DI, 3 LR), timed. Tag misses (Scale, Base, Weight, Diagram, Branching, Logic).
2. Deep fix: redo 1 set per tag with written steps; build template diagrams.
3. Retest: 4 fresh sets; aim higher accuracy on previously weak tags.
4. Summarize: update 1-page toolkit; add 3 exemplar solved diagrams.