Fourth Street lighting shows a net income of $224,000 for the previous year. If the contribution rate for the store was 40.3% and the fixed costs was $315,000, what were last years sales? Solve using the info below

NI = $224 000, CR = 0.403, FC = $315 000

NI = S - TC = S - (FC + TVC)

CR = CM/S = (S - TVC)/S

S = 539 000 + TVC = 539 000 + 798 468.98 = 1 337 468.98

My question is: How to get the value of the Total Variable Cost? Thank you!