Data Interpretation and Logical Reasoning
Data Interpretation and Logical Reasoning
This section (33 questions) mixes chart and table interpretation with puzzle-style reasoning. DI rewards careful reading of axes, units, and totals; LR rewards translating conditions into a compact diagram or table.
Core rules
- Angle to value: in a pie chart, value = (angle/360) × total. A 72° slice of ₹48,000 is ₹9,600.
- Percentage of total: compute the total first; never compare raw slice values without checking the denominator.
- Approximation: options are usually spaced, so round to two significant figures, but keep one exact step for the final choice.
- Arrangements: fix the most constrained position first; draw slots rather than writing prose.
- Blood relations: use a family tree with gender markers; do not assume gender from a relation word.
- Syllogism: draw minimal Venn diagrams; a conclusion is valid only if true in every possible diagram.
- Direction sense: track net displacement with a coordinate sketch.
Worked example
A pie chart of monthly expenditure totals ₹48,000; rent is 90°. Rent = 90/360 × 48,000 = ₹12,000. If rent rises 10%, new rent = ₹13,200, which is 27.5% of the old total (13,200/48,000). If the new total also rises, recalculate the denominator - do not reuse 48,000.
Traps
Mixing lakh and crore, or thousands and rupees. Treating a percentage-point rise as a percent rise. For “cannot be determined” questions, check whether multiple arrangements satisfy the clues. In DI, the question may ask for a ratio, not a difference.