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Line Graph Data Interpretation: Trends, Growth and Gaps

Read the trend • Steepest rise vs biggest percentage rise • Falls • Two lines and their gap

SSC Banking 📅 Last updated: 2026-10-24

A line graph plots values in order, usually over time, and joins them with straight lines. Its strength is showing the trend: where the values rise, where they fall and where they change fastest. Exam questions on line graphs ask about exactly those features, plus the usual totals, averages and ratios.

The graphs on this page show invented practice data. The first is the number of monthly visitors to a museum, in thousands.

Line graph: monthly visitors to a museum, in thousands, January to June01020304050Thousand visitorsJanFebMarAprMayJun243027364542
Monthly museum visitors (thousand), January to June.

As with any chart, first check the unit (thousand visitors), the gap between gridlines (10) and the labels on the horizontal axis. Then look at the overall shape: a rise to May with dips in March and June.

Percentage change between two points uses the earlier point as the base: (new − old) ÷ old × 100. A fall gives a negative change, and the question will usually say "decrease", so report it as a positive percentage decrease.

Worked example 1: rise between two months

Visitors rose from 24 thousand in January to 30 thousand in February. Increase = (30 − 24) ÷ 24 × 100 = 25%.

Worked example 2: the biggest percentage rise

The rises are Jan–Feb (6 on 24), Mar–Apr (9 on 27) and Apr–May (9 on 36). Two segments rise by 9, but the one starting lower wins: 9 ÷ 27 × 100 = 33.33%, from March to April.

Worked example 3: a fall

From May (45) to June (42), visitors fell by 3. Decrease = 3 ÷ 45 × 100 = 6.67%.

Worked example 4: average over the period

The six points add to 24 + 30 + 27 + 36 + 45 + 42 = 204, so the monthly average is 204 ÷ 6 = 34 thousand.

Graphs with two lines add a new kind of question: the gap between the lines and where they cross. The second graph shows a country's exports and imports in ₹ thousand crore (again invented data).

Line graph: exports and imports of a country, ₹ thousand crore, 2021 to 2025050100150200250₹ thousand crore20212022202320242025120150135180200140160170175210ExportsImports
Exports and imports (₹ thousand crore), 2021 to 2025.
Year20212022202320242025
Exports120150135180200
Imports140160170175210
Imports − exports201035−510

Worked example 5: trade deficit in one year

In 2023 imports were 170 and exports 135, so the trade deficit was 170 − 135 = 35 thousand crore, the widest gap on the graph.

Worked example 6: where the lines cross

Exports were above imports in only 1 year, 2024 (180 against 175). On the graph, that is the only point where the exports line sits above the imports line, so the lines cross twice: between 2023 and 2024, and again between 2024 and 2025.

Worked example 7: one line as a percentage of the other

In 2025, exports were 200 ÷ 210 × 100 = 95.24% of imports.

Adding a "gap" row to your rough table, as above, turns several questions into simple look-ups.

  • ✘ Treating the steepest segment as the largest percentage change without checking the base.
  • ✘ Mixing up which line is which in a two-line graph; read the legend before the data.
  • ✘ Reporting a surplus year as a deficit because you subtracted in the wrong order.
  • ✘ Reading points between gridlines carelessly when values are not printed.
Question asksMethod
Largest percentage riseCompare change ÷ starting value for each segment
Percentage fall(old − new) ÷ old × 100
Gap between two linesSubtract point by point; note the sign
Years one line is above the otherCount the points where it is higher
AverageSum of points ÷ number of points

The same arithmetic appears in bar graph DI and table DI. If the numbers are awkward, use approximation for DI; for averages, see average formulas and the Quant cheat code.

Q1. Using the museum line graph, how many visitors (in thousands) came in the first three months together? easy

✅ Answer: (c) 81

💡 Explanation: January, February and March show 24, 30 and 27 thousand visitors. Their sum is 24 + 30 + 27 = 81 thousand.

Q2. By what percentage did visitor numbers rise from March to May? medium

✅ Answer: (b) 66.67%

💡 Explanation: Visitors rose from 27 to 45 thousand, a rise of 18 on a base of 27. 18 ÷ 27 × 100 = 66.67%. The 18 alone is the change, not the percentage.

Q3. In the exports–imports graph, what was the largest trade deficit (imports minus exports) in any year, in ₹ thousand crore? medium

✅ Answer: (d) 35

💡 Explanation: The yearly gaps are 20, 10, 35, −5 and 10. The widest gap with imports above exports is 35, in 2023. In 2024 exports were higher, a surplus.

Q4. By what percentage did imports increase from 2021 to 2025? easy

✅ Answer: (a) 50%

💡 Explanation: Imports grew from 140 to 210, a rise of 70 on a base of 140, so 70 ÷ 140 × 100 = 50%. Using 210 as the base gives 33.3%, a trap.

Q5. What was the ratio of exports to imports in 2022? easy

✅ Answer: (c) 15 : 16

💡 Explanation: In 2022 exports were 150 and imports 160. 150 : 160 simplifies by 10 to 15 : 16. The reverse order, 16 : 15, is the trap option.

Q6. What were average annual exports over 2021–2025, in ₹ thousand crore? easy

✅ Answer: (b) 157

💡 Explanation: Exports were 120, 150, 135, 180 and 200, which add to 785. Divided by 5 years, the average is 157.

Is the steepest part of a line graph always the largest percentage increase?

No. A steep segment shows the largest absolute change, but percentage change also depends on the starting value. A rise of 9 from 27 is 33 percent, while a rise of 9 from 36 is only 25 percent, even though both look equally steep.

When should I use a line graph question's options to save time?

When the options are well spread out, estimate. Round each point to a nearby friendly number, work out the rough answer and pick the closest option. Only calculate exactly when two options are close together.

All problems and solutions on this page are original. No outside facts are relied on; every numeric answer is recomputed by software before publishing.

How this page was prepared. Drafted with AI assistance (Claude (Anthropic AI model)) from the sources listed above. 13 calculations on this page were recomputed by software and matched. Automated checks also covered structure, internal links and duplicate text. Software checks cannot confirm facts. Reviewed by praveenkumar on 2026-10-24 against the sources listed above.

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