Fran will have a base amount of $800 saved at the end of the 20 weeks assuming she continues to get at least 15 hours and her expenses don't increase (40x20 =800). At a net pay rate of $15 per hour (225/15=15), she will need to work an additional two hours per week for a total of 17 hours to earn the $600 needed to meet her goal. [15x2= 30, 30x20=600]