The rate is 16.1% and the base is the final portion with the rate added on to it.
Chance the percentage into a decimal.
16.1% / 100 = 0.161
Multiply.
454 * 0.161 = 73.094
Add.
454 + 73.094 = 527.094 or 527.09
Therefore, the final base is roughly 527.09
Best of Luck!