In Bar graph,
We made a table to a bar graph
| 
     Class  | 
   
     5 th  | 
   
     6 th  | 
   
     7 th  | 
   
     8 th  | 
   
     9 th  | 
  
| Number of girls | 30 | 35 | 20 | 25 | 40 | 
 
 
But,
What if we have data like this
| 
     Class  | 
   
     5 th  | 
   
     6 th  | 
   
     7 th  | 
   
     8 th  | 
   
     9 th  | 
  
| Number of girls | 30 | 35 | 20 | 25 | 40 | 
| Number of boys | 20 | 40 | 25 | 35 | 20 | 
Here, we make a double bar graph.
Since number of students are from 20 to 40
We draw bar graph from 0 to 45
with a gap of 5
 
 
Let’s take another example
Suppose population of India & China are
| 
     
  | 
   
     1951  | 
   
     1961  | 
   
     1971  | 
   
     1981  | 
   
     1991  | 
   
     2001  | 
  
| 
     Population of India (in crores)  | 
   
     36  | 
   
     44  | 
   
     54  | 
   
     68  | 
   
     84  | 
   
     102  | 
  
| 
     Population of China (in crores)  | 
   
     58  | 
   
     64  | 
   
     70  | 
   
     90  | 
   
     100  | 
   
     110  | 
  
Here, population is from 36 to 110
we draw graph from 0 to 110 with gap of 10