the process is 50% complete. The company uses the FIFO method of cost allocation.
What are the equivalent units of production for materials in the period?
You have to read the question carefully: What are the equivalent units of production for MATERIALS in the period?
The % completions for op/cl WIP relate to labour and overheads - not material. 3/4 (75%) of materials goes in at the start of the process - and the remaining 25% when the process (as shown by labour and o/head %s) is 50%.
In other words - opWIP was already complete with respect to materials, because 60% > 50% - so EU for materials in the current period is 0. And cl WIP has 75% of materials, because 20% < 50%.