Data Interpretation: notes & practice

Tables, bar charts, pie charts, line graphs, caselets and mixed DI — a high-weight section in IBPS/SBI PO, RRB and SSC CGL.

Key topics

• Tables

  Read row and column headers first; compute only the asked cell; use ratios and differences.

• Bar & Line Charts

  Estimate values from the axis scale; look at growth rates and trends.

• Pie Charts

  Convert sectors to degrees or percentages of the total; central angle = share × 360°.

• Caselets

  Paragraph-based data; write the given facts as small equations before solving.

• Speed Calculations

  Fraction-percentage table (1/8 = 12.5%, 1/6 ≈ 16.67%), approximation, ratio comparison.

• Common Tricks

  Successive change a + b + ab/100, share of a part = (part/total) × 100, growth = (new − old)/old.

Practice questions

Our own practice questions in the style of past papers.

1. 1. In a pie chart of ₹2,00,000 expenses, one sector is 45°. Its value is:

   A. ₹20,000B. ₹25,000C. ₹30,000D. ₹40,000

2. 2. Sales rose from 400 to 450 units. Percentage increase is:

   A. 10%B. 12.5%C. 15%D. 20%

3. 3. A pie chart's total central angle is:

   A. 180°B. 270°C. 360°D. 540°

4. 4. Production is 1,200 units and defect rate is 2.5%. Defective units are:

   A. 25B. 30C. 35D. 40

5. 5. Profit grew 20% in year 1 and 25% in year 2. Total growth is:

   A. 45%B. 50%C. 48%D. 55%

6. 6. Average of five readings is 40. One reading 50 is replaced by 70. New average is:

   A. 42B. 44C. 46D. 48