Introduction
Data Interpretation (DI) doesn't test new formulas — it tests whether you can accurately read a table,
bar graph, pie chart, or line graph and then apply concepts from earlier chapters (mainly Percentage,
Ratio, and Average) quickly and correctly.
The Four Standard DI Formats
| Format | What It Shows | Key Skill Needed |
|---|
| Table | Exact numerical values in rows/columns | Careful reading, avoiding row/column mix-ups |
| Bar Graph | Comparison of values across categories using bar height/length | Reading the value axis scale correctly |
| Pie Chart | Parts of a whole, shown as proportional slices (in % or degrees) | Converting degrees ↔ percentage ↔ actual value |
| Line Graph | Trend of a value over time/categories | Reading rate of change/slope between points |
Pie Chart — Degree/Percentage Conversion
Flowchart — Pie Chart Core Conversion
Full circle = 360° = 100%
↓
Value's % share = (Value's degree / 360) × 100 | Value's degree = (%share/100) × 360
Q. In a pie chart, a sector representing "Transport" expenses occupies 72°. If the total monthly expense is ₹50,000, find the amount spent on Transport.
% share = (72/360) × 100 = 20%
Amount = 20% of 50,000 = ₹10,000
Bar Graph — Comparison Questions
Q. A bar graph shows sales (in units) of a company: Jan=200, Feb=250, Mar=180, Apr=270. Find the percentage increase in sales from March to April.
Increase = 270−180 = 90
% increase = (90/180) × 100 = 50%
Table-Based DI — Ratio/Average Combination
Q. A table shows marks of 5 students in 4 subjects. If the total for Student A across all subjects is 340 out of 400, find A's overall percentage.
Percentage = (340/400) × 100 = 85%
Line Graph — Trend and Rate of Change
Q. A line graph shows a company's profit (₹ lakh): 2020=40, 2021=50, 2022=45, 2023=60. Find the average annual profit over these 4 years.
Average = (40+50+45+60)/4 = 195/4 = ₹48.75 lakh
Common DI Sub-Question Types
- "Find the difference" — direct subtraction between two data points.
- "Find the ratio" — express one value as a ratio of another (simplify fully).
- "Find the % change" — apply the standard percentage-change formula from Chapter 6.
- "Find the average" — apply the average formula from Chapter 8 across the given data points.
💡 Exam Tip: DI questions are often grouped as a set of 4-5 questions per graph/table — spend the first 20-30 seconds just reading and understanding the data structure fully before attempting any calculation; this avoids costly re-reading errors across multiple questions.
✅ Practice Focus: Pie chart degree-percentage-value conversion · Bar graph percentage-change reading · Table-based ratio/average/percentage combination questions · Line graph trend and average calculations.