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Data Table

Competitive Mathematics · Data Interpretation

6 Part3 worked examples12 practice questions

A train timetable, a bank passbook, a mark sheet — all are tables: figures arranged in rows (horizontal) and columns (vertical). A table holds far more figures than a pie or bar chart, which is why it gives the most questions in competitive exams. The key is simple: read the right cell first (where the row meets the column), then use the arithmetic you already know — average, ratio, percent, percent increase.

Three tools for table questions
1

Reading a table

Row, column, unit

The layout of a table, reading cells and direct sum-and-difference questions.

Reading cells and direct calculations

First the right cell, then the arithmetic

The sum, average or difference of a cell, a row or a column.

Below is a fruit-seller’s sales for five days. Learn the rules from it: row = day, column = fruit. “Bananas on Wednesday” is where the Wednesday row meets the Bananas column — that is kg.

DayApples (kg)Bananas (kg)Mangoes (kg)
Monday408030
Tuesday557045
Wednesday359050
Thursday606040
Friday507535
  • Check the unit: the unit in the title or column heading (kg, ₹ lakh, thousand) carries into the answer. If units differ, make them alike first.
  • A column total is added downwards, a row total across. Average = total ÷ count — the count is the number of items you added.
  • “How much more/less” = difference (subtract); “how many times” = divide; “what percent” = part ÷ whole × 100.
Example 1 · Basic
From the table above: the total banana sales over the five days and the daily average.
Solution, step by step
  1. 1Bananas column: kg.
  2. 2Average kg per day
Answer 375 kg; 75 kg
Example 2 · Standard
From the table above: the apples sold on Wednesday are about what percent of that day’s total sales?
Solution, step by step
  1. 1Wednesday’s total kg.
  2. 2
Answer 20%
Example 3 · Standard
From the table above: the ratio of apples to mangoes sold on Tuesday.
Solution, step by step
  1. 1Apples , mangoes .
  2. 2Ratio
Answer 11 : 9

Table: Production of crops (in thousand tonnes). Study the table and answer the questions.

YearWheatRiceMaizePulses
2018340430210125
2019370460210130
2020370500220140
2021380540230140
2022390570230150
2023410600230160
BasicTry it yourself first
Find the total of “Pulses” over all the rows (in thousand tonnes).
BasicTry it yourself first
Find the total over all columns for “2022” (in thousand tonnes).
BasicTry it yourself first
Find the sum of “Wheat” in “2022” and “Pulses” in “2022” (in thousand tonnes).
BasicTry it yourself first
Find the difference between the values of “Maize” for “2021” and “2018” (in thousand tonnes).
BasicTry it yourself first
Find the average value of “Wheat” over all the rows (in thousand tonnes).
BasicTry it yourself first
Find the ratio of “Wheat” in “2021” to “Rice” in “2021”.

Table: Marks of five students (out of 100 in each subject). Study the table and answer the questions.

StudentHindiEnglishMathsScienceSocial
Anil6050758555
Bina5070757075
Chetan5080657075
Deepa7565858555
Esha6075707055
BasicTry it yourself first
Find the total over all columns for “Anil” (in marks).
BasicTry it yourself first
Find the total of “Maths” over all the rows (in marks).
BasicTry it yourself first
Find the average of all the columns for “Chetan” (in marks).
BasicTry it yourself first
Find the difference between the values of “Science” for “Anil” and “Chetan” (in marks).
BasicTry it yourself first
Find the sum of “Maths” in “Chetan” and “English” in “Chetan” (in marks).
BasicTry it yourself first
Find the ratio of “Maths” in “Bina” to “Social” in “Deepa”.
2

Average, ratio and percent questions

One step beyond reading

Percent, percent increase, comparison with the average and spotting the highest or lowest row or column.

Percent and comparison

Part ÷ whole × 100

One cell as a percent of another; the share of a row total; how many are above the average.

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Combined and higher-level questions

Several cells, several steps

The share of two columns together, the column with the highest growth, the difference of two row sums.

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3

Special kinds of table

Percents, missing values and rates

Tables where the figures are percents, some values are hidden or quantity and rate are given.

Percents, missing values and quantity–rate

Digging out hidden numbers

Three special tables and how to handle each.

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4

Traps and fast tricks

Slips · tricks

Where marks go in table questions.

The commonest mistakes

Seven traps

The slips that cost marks.

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Fast tricks

Less calculation, more thinking

Habits for speed.

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5

The practice ladder

Basic → standard → advanced

New tables and questions of every type, in three levels.

Level 1 — Basic

Direct sums, averages, differences

One-step questions.

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Level 2 — Standard

Percent, growth, comparison

Exam-level questions.

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Level 3 — Advanced

Many steps and mixed tables

Questions at the hard end of competitive exams.

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6

Revision — formula cards

Flip each card and test yourself

Read the front, think, then flip.

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