The first unit of production requires 125 hours. The average time required for the first two units is 80 percent of the time, or 100 hours. Thus, the first two units require 200 total hours. When cumulative output doubles again, from two units to for unit, the average time required for the first four units is 80 percent of that required for the first two units, or 80 hours. The first four units require 320 total hours. This reduction continues, reducing labor time per unit.