Question: how to calculate percentage of one rep max?
Answer: Start by computing your 1RM; just divide 245 pounds by 0.80, which estimates your single-rep max to be 306.25, which can be rounded down to 305. To find your 3RM, note that 3 corresponds to 93% 1RM, so multiply 305 x 0.93, which estimates your working weight to be 285 (rounded up) pounds.