To determine the equivalent unit cost under FIFO, current period costs are divided by the number of equivalent units for total work performed this period. During May, equivalent unit costs are calculated as shown above: $3.05 for direct materials ($30500 / 10000 units) and $7.10 for conversion costs ($76 800 / 10 800 units). These costs are allocated to the work performed to complete beginning WIP ($9940), to the units started and completed ($91 350), and to the equivalent units in ending WIP ($5890. We can double-check our calculations by verifying that the sum of costs accounted for ($9940 $91 350 + $5890) is equal to the costs incurred this period of $107 180. To determine the costs of goods transferred to the assembly department we must also add the cost incurred for the beginning WIP units during April, which is recorded at $10200. Therefore, the cost of goods transferred equals $111 490