Data Interpretation: Ratio and Proportion
What This Skill Is
Every question in CLAT's Quantitative Techniques section is built the same way: a data set (typically 94–299 words) -- a table, a bar chart, a pie chart, or a few lines of text stuffed with numbers -- followed by 6 questions (5 in the pre-2024 papers) that test different skills on the same underlying data. Ratio & Proportion is one of the most frequent skills tested this way.
In practice, this means you will be given quantities (populations, revenues, votes, ingredients, distances) and asked to compare them relatively rather than in absolute terms. Typical question stems look like:
- "What is the ratio of X to Y?"
- "If the ratio of A to B is maintained, what will C be when A becomes...?"
- "What is the ratio of the two groups after the stated change?"
- "By what ratio did the two values change relative to each other?"
The twist that makes this a CLAT skill rather than a plain arithmetic drill is that you must first extract the right two (or three) numbers from a paragraph or chart cluttered with other data, and only then do the ratio math. The reading and locating is often harder than the calculation itself.
Step-by-Step Strategy
With roughly one minute per question, you cannot afford to re-read the whole passage for every question. Work like this:
- Skim the passage/data set once for structure, not detail. Note what categories exist (years, products, regions) and roughly where each number lives. Do not memorise values.
- Read the question stem carefully and identify exactly which two quantities are being compared. Underline or mentally flag them -- ratio questions fail most often because students compare the wrong pair.
- Locate only those specific numbers in the passage or table. Do not scan the entire data set again.
- Check the units and base before dividing. Are both quantities in the same unit (rupees, kg, percent, count)? Is one a total and the other a subset? Mixing a percentage with a raw count is the single most common error.
- Simplify the ratio to its lowest terms unless the question specifically asks for a decimal, a percentage, or an unreduced form.
- Re-read the question once more before selecting an answer -- confirm it asks for A:B and not B:A, or "increase in ratio" and not "the new ratio itself."
- Eliminate options that are inverted or scaled wrong (e.g., 3:5 vs. 5:3) before comparing the remaining ones -- this catches your own errors fast.
Common Traps
- The inverted ratio trap: Answer choices routinely include both A:B and B:A. Circle which one the question actually wants before you touch the numbers.
- Mismatched bases: One figure in the passage may be "out of total enrolled" and another "out of those who appeared" -- dividing them directly gives a ratio that means nothing.
- Percentage-vs-value confusion: A passage may state a percentage share for one category and an absolute figure for another; you must convert both to the same form before forming a ratio.
- Unreduced vs. reduced form: 12:18 and 2:3 are the same ratio, but if the options offer both, always check what form the question demands.
- Combining three quantities into a two-term ratio (or vice versa): Watch for questions like "find A:B:C" where a careless student computes only A:B.
- Irrelevant numbers planted nearby: CLAT passages often place a decoy figure (a different year, a different sub-group) right next to the number you need -- this is deliberate. Confirm the label, not just the position, before using a number.
Worked Example
Passage (original)
A community library in Mysuru tracked its membership renewals over two consecutive years. In Year 1, the library had 480 adult members and 320 student members. In Year 2, following a fee revision, adult membership rose to 540, while student membership, boosted by a new outreach programme, rose to 480. The library also noted that of the Year 2 student members, 180 had joined through the outreach programme specifically, while the rest had renewed from the previous year.
Question
What is the ratio of adult members to student members in Year 2?
A) 4:3
B) 9:8
C) 3:2
D) 27:16
Reasoning
The question asks specifically for Year 2 adult members : Year 2 student members. Locate those two figures precisely -- Year 2 adult members = 540, Year 2 student members = 480 (not the 180 outreach figure, which is a subset planted as a distractor for a different question about the outreach programme's share).
Ratio = 540 : 480. Divide both by their GCD, 60: 540/60 = 9, 480/60 = 8.
Ratio = 9 : 8 -> Option B.
Why the traps fail
Option A (4:3) does not correspond to any direct combination of the passage's real figures and exists purely to tempt a rushed guess. Option D (27:16) is 540 : 320 reduced -- Year 2 adults against Year 1 students. It catches anyone who located the adult figure correctly but took the student figure from the wrong year. Option C (3:2) is actually the Year 1 ratio (480:320 reduced), catching anyone who read the passage too fast and grabbed the first pair of numbers they saw instead of confirming which year the question asked about.
The lesson: identify the exact quantities and time period requested, extract only those, reduce carefully, and double-check the direction of the ratio before locking in your answer.
What the exam tests here
Across the 3 papers we hold, this skill was asked 6 times, around 2 a paper.
What it actually asked:
- DI — annual gas:hydro ratio (2026)
- DI — insured ratio urban:rural (2026)
- DI — ratio (2.8x earnings) (2025)
- DI - ratio between two cells (2024)
- DI - ratio of two groups (2024)
- DI - ratio under new condition (2024)
Practise Data Interpretation: Ratio and Proportion
This skill's 4 free questions are passage-based, the way the CLAT UG paper sets them, so they are practised in the app where the passage sits beside each question.
Practise free in the app