Computing equivalent units, FIFO and average cost methods

{Assume each of the following conditions concerning the data given:}

1. All materials are added at the beginning of the process.

2. All materials are added at the end of the process. (Note that this would have to be a department subsequent to the first department for all materials to be added at the end of the process.)

3. Half of the materials are added at the beginning of the process and the balance of the materials are added when the units are threefourths completed.
In all cases, labor and factory overhead are added evenly throughout the process.

Units Production Summary Dept. 1 Dept. 2 Dept. 3 Work in process, beginning of month 3,000 1,500 1,200 Stage of completion...... 1/2 3/5 4/5 Started in process.... 18,000 16,000 21,000 Finished and transferred 19,000 15,500 21,000 Work in process, end of month 2,000 2,000 1,200 Stage of completion 1/4 4/5 1/5 Compute separate equivalent units of production, one for materials and one for labor and factory overhead, for each of the conditions listed, using (a) the average cost method and (b) the FIFO cost method.