How to change range of a Chart

[ThrottleWorks]

Hi,

Please see attached file. I need help for changing range of a Chart.
As per the attached file, number of months in a week can be 4 or 5.

I need to edit chart range accordingly. Can anyone please help me how to do this.
Please see attached file for your reference.

 

[Hui]

Use Named Formulas
see attached

 

[ThrottleWorks]

@Hui sir, you are awesome ! Thanks a lot.