At noon joyce drove to the lake at 30 mph, but she made the long walk back home at 4 mph. how many hours did she walk if she was gone for 17 hours

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