The Ward family and the Martinez family each used their sprinkders last summer. The water output rate for the Ward family's sprinkder was 15 L per hour. The water output rate for the Martinez family's sprinkler was 35 L per hour. The families used their spriniders for a combined total of 40 hours, resulting in a total water output of 900 L. How long was each sprinkder used? Note that the ALEKS graphing calculator can be used to make computations easier. Ward family's sprinkder: hours Martinez family's sprinkder: hours 3 ?