A work center has one machine that is operated for one shift per day. The shop runs an 8-hour shift 5 days per week. Machine utilization has been 60% with efficiency at 80%. A routing through this work center has a standard run time of .10 hours per piece. Job number 1234 is for 200 pieces. If the utilization is improved to 80%, the difference in calculated lead time for the job is how many days?