By definition we have the following equation: t = d / v Where, t: time d: distance v: speed For this case we have: d / 30 + d / 4 = 17 Rewriting we have: 2d + 15d = 17 (60) 17d = 17 (60) d = 60 mi Then, the walking time is t = d / v t = 60/4 t = 15 hours Answer: She walked t = 15 hours