There are 454 grams in a pound. There are 16 ounces in a pound.
How many grams are in an ounce?
There are 454/15= 30.266666666... grams in an ounce.
The rounded answer would be 30.27.
Note, there are 16 ounces in a pound, so I'm not sure if you intentionally made it 15
In that case, 454/16= 28 3/8 grams in an ounce.