**Note:** Before solving the data interpretation questions, you need to learn some useful topics as Percentage, Ratio and Proportion, Average, Profit and Loss. To learn these topics please go to Quantitative Aptitude section.

**Type of Bar Diagrams:** There are mainly two types of bar diagrams discussed below.

**(1). Simple Bar Diagram:** When only one set of data in the form of bars represented then it is called a simple bar diagram.

**Example:** The balance sheet of a company is given below in the form of a simple bar diagram.

**(a):** Average profit from 2012 to 2015. $$ = \frac{100 + 150 + 200 + 150}{4} $$ $$ = \frac{600}{4} = 150 \ Thousand $$

**(b:)** Annual average growth rate. $$ = \frac{150 - 100}{100} \times \frac{100}{3} $$ $$ = 16.66 \ \% \ Per Year $$

**(c): Annual growth rate from 2012 to 2015.**

Growth rate during 2012 to 2013. $$ = \frac{150 - 100}{100} \times 100 $$ $$ = 50 \ \% $$

Growth rate during 2013 to 2014. $$ = \frac{200 - 150}{150} \times 100 $$ $$ = 33.3 \ \% $$

Growth rate during 2014 to 2015. $$ = \frac{150 - 200}{200} \times 100 $$ $$ = -25 \ \% $$

**(2). Multiple Bar Diagram:** When multiple sets of data in the form of bars represented then it is called a multiple bar diagram.

**Example:** The balance sheet of the company A and Company B is given below in the form of a multiple bar diagram.

**Growth rates of company A and B in percentage during the years 2014 to 2015.**

Growth rate of company A. $$ = \frac{100 - 75}{75} \times 100 $$ $$ = 33.3 \ \% $$

Growth rate of company B. $$ = \frac{150 - 125}{125} \times 100 $$ $$ = 20 \ \% $$

**Average profit of company A and B during the years 2014 to 2015.**

Average profit of company A. $$ = \frac{75 + 100}{2} $$ $$ = 87.5 \ Thousand $$

Average profit of company B. $$ = \frac{125 + 150}{2} $$ $$ = 137.5 \ Thousand $$