No you cannot.
No because 185/254 is already in its simplest form
62/21 will not reduce. they have no common factor except 1. You an convert it into a mixed number by dividing.
Rounded to the nearest percentage, it is 62%.
19/185 =0.1027
185 / 100 is equal to 1.85 or 185% or 1 17/20
It is approx 62%. As to the grade, the answer will depend on any normalisation and grade boundaries.
28/185
62 over 7 = 8.857
62 over 495 is the same as 62 divided by 495: 62 / 495 = 0.12525252525253
185/1000 = 37/200
128/185 = 0.6'918' recurring 918
16/62 = 16 ÷ 62 = 0.2581