Answer:
The 20% tip would be 18%
The 80% mark down would be 0.8 I think
The 60% I'm not sure for the 60% one
The 10% I'm not sure for that one but I think it would be 3.75
I think for 75% mark down it would be 0.7 I'm not sure tho and I'm not sure for the rest
Sorry if I'm wrong but hope this helps:)