Beginning work in process cost $17.44 per unit and was 20% complete, and conversion costs $20.40 per equivalent unit in May. What is the finished cost per unit of that opening group?

1. The opening group already carries $17.44 per unit, which is 100% of its materials plus the 20% of conversion done in April. 2. Only the remaining 80% of conversion is added in May. 3. That May conversion is $20.40 times 80%, which is $16.32 per unit. 4. Finished cost per unit is $17.44 plus $16.32, which is $33.76. 5. $37.84 adds a full $20.40 of conversion and so charges the 20% already paid for in April a second time. 6. $29.73 replaces the carried cost with the May materials rate of $13.41, which does not apply to units whose materials went in during April. 7. $21.52 adds only 20% of conversion, the share that had already been done rather than the share still to come. _Source: Jonick, Principles of Managerial Accounting (UNG Press, CC BY-SA 4.0), section 3.3 Process Costing Calculations for a Department in a Manufacturing Company_