Want to make formula to percentage slab

I want insert a formula in excle which can help to know the slab comes under which percentage slab 

Example 

If resolution is 

1% then slab will be update as 0-30%slab 

31% then slab will be update as 30-50%

51% then 50-80%

81% then 80-100%

101% then it have to show morethen 100%

Every time I am doing this manually but it taking so many time if I update resolution coloum can percentage slab colunm will update automatically as I need 

Plz help out of this if possible 

Thank u