Paper IPaper I · General Mental Ability

Data Interpretation

Reading tables, bar and line graphs, and pie charts fast, with worked sets and practice

CAPF wiki•5 min read•10 sections

At a glance

PaperPaper ISubjectGMASyllabusGeneral Mental Ability: data interpretationImportanceHigh

GMAData InterpretationTablesBar GraphLine GraphPie ChartPaper 1

Data interpretation (DI) tests whether you can extract and compute from a chart quickly, not whether you can do hard maths. The arithmetic is almost entirely percentages, ratios, and averages, so percentage ratio and average is the prerequisite. The marks come from reading the chart correctly and computing fast.

The four common chart types

Type	What it shows	Watch for
Table	Exact values in rows and columns	Units in the header; totals row or column
Bar graph	Comparison across categories	Axis scale and starting value
Line graph	Trend over time	Slope direction; the gap between two lines
Pie chart	Share of a whole (parts of 100% or 360°)	Whether values are percent or degrees

Pie-chart conversions

From	To	Rule
Degrees	Percent	(degrees / 360) times 100
Percent	Degrees	(percent / 100) times 360
Percent	Value	percent times total

A full circle is 360°, so 1% equals 3.6°, and 90° equals 25%.

How to read fast

Read the title, the axis labels, and the units before looking at any number. Half of DI errors are unit errors (lakhs versus crores, percent versus absolute).
For "by what percent is A more than B", the base is B: ((A - B)/B) times 100. For "A is what percent of B", it is (A/B) times 100. These are different.
Estimate first. If options are far apart, an approximation decides the answer without exact computation.
For pie charts given in percent, never re-compute the total share; it is fixed at 100%.
Do the comparison the question asks, not a harder one. "Which year had the highest growth" needs differences, not totals.

Worked set 1: table

A table gives the number of recruits trained at an academy across three years.

Year	BSF	CRPF	CISF	Total
2023	400	600	200	1200
2024	500	700	300	1500
2025	600	800	400	1800

Question 1: What is the percentage increase in total recruits from 2023 to 2025? Change = 1800 - 1200 = 600. Percent = (600 / 1200) times 100 = 50%.

Question 2: In 2024, what fraction of total recruits were CRPF? 700 / 1500 = 7/15, which is about 46.67%.

Question 3: What is the average number of CISF recruits per year? (200 + 300 + 400) / 3 = 900 / 3 = 300.

Worked set 2: pie chart

A family's monthly expenditure of Rs 36,000 is split as: Food 30%, Rent 25%, Education 20%, Savings 15%, Others 10%.

Question 1: How much is spent on Rent? 25% of 36000 = 0.25 times 36000 = Rs 9,000.

Question 2: What is the angle of the Education sector in degrees? 20% of 360 = (20/100) times 360 = 72°.

Question 3: By how much does Food exceed Savings in rupees? Food = 30% = 10800, Savings = 15% = 5400. Difference = Rs 5,400. (Equivalently 15% of 36000.)

Worked set 3: bar or line comparison

A line graph shows a company's profit (in Rs crore): 2021 = 20, 2022 = 25, 2023 = 24, 2024 = 30, 2025 = 36.

Question 1: Which year saw the highest percentage growth over the previous year? 2022 over 2021: (5/20) times 100 = 25%. 2024 over 2023: (6/24) times 100 = 25%. 2025 over 2024: (6/30) times 100 = 20%. 2022 and 2024 tie at 25%, both higher than 2025's 20%, and 2023 fell.

Question 2: What is the average annual profit over the five years? (20 + 25 + 24 + 30 + 36) / 5 = 135 / 5 = Rs 27 crore.

Question 3: In which year did profit fall, and by what percent? Profit fell in 2023 (25 to 24). Fall = (1/25) times 100 = 4%.

Shortcut tips

Convert pie percentages to rupees once, write them in the margin, then answer every sub-question from your own list.
"Growth rate" questions need previous-year as the base; do not divide by the later year.
When a chart mixes a table and a graph, the table usually holds the exact numbers; trust it over the eyeballed bar.
For average-of-several-years questions, sum once and reuse the sum across sub-questions.
If two options differ by less than 2%, do the exact computation; otherwise estimate.

Practice questions

Use the expenditure pie chart from Worked set 2 (total Rs 36,000) for questions 1 to 3.

How much is spent on Food and Education together?
What is the central angle of the Savings sector?
Others spending is what percent of Rent spending?

Use the recruits table from Worked set 1 for questions 4 to 6.

What is the percentage increase in CRPF recruits from 2023 to 2025?
In 2025, what percent of the total were CISF recruits?
What is the average total recruits per year over the three years?

Use the profit line graph from Worked set 3 for questions 7 to 9.

What is the total profit over the five years?
By what percent did profit rise from 2021 to 2025?
What is the difference between the highest and lowest annual profit?
In a pie chart, a sector measures 54°. What percent of the whole does it represent?

Answer key

Reveal the answer key and full worked solutions

Food 10800 + Education 7200 = Rs 18,000.
15% of 360 = 54°.
Others 10%, Rent 25%, so (10/25) times 100 = 40%.
(800 - 600)/600 times 100 = (200/600) times 100 = 33.33%.
400 / 1800 = 22.22%.
(1200 + 1500 + 1800)/3 = 4500/3 = 1500.
135 (Rs crore).
(36 - 20)/20 times 100 = (16/20) times 100 = 80%.
Highest 36, lowest 20, difference = Rs 16 crore.
(54 / 360) times 100 = 15%.