Data Interpretation and Problem Solving
What this section tests
Reading quantitative information from tables, bar charts, line graphs, pie charts and composite figures, then performing multi-step arithmetic on it: shares, growth, ratios, averages and comparisons.
Method
First read the title, the axis labels and the units - thousands, lakhs, millions, percentages. Note whether a pie chart represents one total or several. Then identify exactly which two numbers the question compares; most mistakes in this section are selection errors rather than arithmetic errors.
For comparisons, avoid long division. Compare 3/7 with 4/9 by cross-multiplying: 3 × 9 = 27 and 4 × 7 = 28, so 4/9 is larger.
Traps
- Percentage point versus percent: a share moving from 20% to 25% rises 5 percentage points but 25 percent.
- Pie charts drawn from different totals cannot be compared segment by segment without converting to absolute values.
- Growth rates computed against the wrong base year.
- Stacked bars: read a segment's own height, not the top of the stack.
- Rounding too early; keep full precision until the final step.
Worked example
Sales are 40,000 units in Year 1 and 50,000 in Year 2. Growth is (50,000 − 40,000) ÷ 40,000 = 25%. A distractor will offer 20%, obtained by dividing 10,000 by 50,000 - that uses the wrong base.
Rule of thumb
Before computing, write down the units and the base. If either is unclear, re-read the chart.