Changing weighting of different rasters in a MCA for site use suitability.

Hi everyone! Apologies if my terminology isn’t correct I’m still very new to all GIS.

I’m doing a site suitability for a hospital for a uni assignment, our instructions are general however it says for extra point to change the weighting of different factors.

I know how to assign different numbers based on distance i.e. 100m at 10, 300m at 5. However I was curious how to change the % whole categories have in masks.

As in social - transport I don’t think distance from roads vs trains should be equally weighted.