Problem:
Susan has a part-time "cottage industry" producing seasonal plywood yard ornaments for resale at local craft fairs and bazaars. She currently works a total of 5 hours per day to produce 10 ornaments
She thinks that by redesigning the ornaments and switching from use of a wood glue to a hot-glue gun she can increase her total production to 20 ornaments per day.
What is her percentage increase in productivity?