I can't seem to figure out how to find the total cost of units in ending goods in process.
Gds in process Jan 1 0 units
Units started in production 18,000 units
Units completed and transferred out 12,000 units
Gds in process Dec. 31 6,000 units
Production Costs:
Direct materials $213,885
Direct Labor 577,500
Factory Overhead 391,875
The units still in process are 45% complete with respect to direct materials and 35% complete with respect to comversion costs.

I can't seem to figure out how the answer is 183,660.