Explain in layman terms "equivalent units of production" (EUP).

How does the calculation of EUP differ between the weighted-average (WA) method and the first-in-first-out (FIFO) method? Which method provides more accurate results, WA or FIFO? Defend your answer on why.

Discuss in detail how a company would determine how many work in process (WIP) accounts to maintain when process costing is employed?