Data Interpretation and Caselets — CLAT Quantitative Techniques

Under the revised pattern, all of CLAT quant is data interpretation — a table, a bar or pie chart, or a caselet, followed by questions. The arithmetic is the percentage, ratio and average you already know; the new skill is reading the data cleanly and pulling the right numbers. This chapter drills the sources — tables, bar and pie charts — and the two conversions the section leans on most: percentage share and the pie-angle ↔ percentage swap.

1. Reading a table

A table lists exact values. The core moves are totals, differences, and shares.

• Sales — A: 200, B: 300, C: 500 → total $=1000$.
• Share of C $=\frac{500}{1000}\times 100=50\%$.

$\text{percentage share}=\frac{\text{category value}}{\text{total}}\times 100$

Read the row and column headings first — most table errors come from lifting the wrong cell.

2. Bar charts — compare heights

A bar chart compares quantities across categories or years. The usual questions:

• Difference between two bars.
• Percentage change across years: $\frac{\text{later}-\text{earlier}}{\text{earlier}}\times 100$.
• Revenue ₹40 lakh → ₹50 lakh: growth $=\frac{10}{40}\times 100=25\%$.

Note the scale and units on the axis — a bar chart in "₹ lakh" or "thousands" is a common units trap.

3. Pie charts — the angle–percentage swap

A pie chart splits a whole ($360°$) into sectors. Convert both ways:

$\text{angle}=\frac{\text{percentage}}{100}\times 360°,\text{percentage}=\frac{\text{angle}}{360°}\times 100$

• 25% of the total → sector angle $=\frac{25}{100}\times 360=90°$.
• A $72°$ sector → $\frac{72}{360}\times 100=20\%$ of the total.

The whole pie is 360° = 100%. Turn a sector into a percentage, then into an actual amount using the given total.

4. From share to amount

Once you have a percentage share and the total, the amount is one step.

• Monthly budget ₹30,000; Rent 40%, Food 30%. Rent $=0.40\times 30000=12000$; Food $=9000$; Rent exceeds Food by ₹3,000.

Chart questions usually end in an amount or a difference — carry the percentage through to the rupee (or unit) figure the question wants.

5. Caselets — data in prose

A caselet hides the table inside a paragraph. Extract the numbers into your own mini-table before computing.

• "Over five days a shop sold 20, 25, 30, 15 and 10 units." Total $=100$; the day with 25% of total (25 units) is Day 2.

Convert the words to a table on your rough sheet; the question then becomes an ordinary table read.

6. The DI method

1. Read the headings, scale and units before any question.
2. Note whether the question wants a total, difference, share, or change.
3. For pie charts, swap angle ↔ percentage, then to the amount.
4. For caselets, rebuild the table from the prose.
5. Re-read the question to confirm the exact cell/period asked.

7. Exam protocol

1. Take in headings, units and scale first — most DI errors are misreads.
2. Use percentage share $=\frac{\text{part}}{\text{total}}\times 100$ for portions.
3. Convert pie angles and percentages with the $360°$ whole.
4. Carry a share through to the actual amount the question asks.
5. Rebuild caselet prose into a table before calculating.
6. Confirm you read the right row, column or period before locking the answer.