Explanation:
please let me know what you don't understand here. because this is really simple.
the distance from home is increasing and then decreasing when she is traveling.
the rate of distance per time would give us even the speed with which she was traveling.
when there is no change in the distance over time, that means she was "stationary" - either at home or at her grandmother's place.
so, let's answer the questions :
(a)
movement started at 7:30am (that is when she began her journey).
(b)
20 miles
you pick 8am on the time scale and move straight up until you hit the curve. and then you check what value is at that point all the way to the left on the distance scale : 20.
(c)
from 8:30am to 10am = 1.5 hours.
we see this by the interval on the time scale for which the curve is totally flat (a horizontal line) = no change in distance from home during that time.
(d)
at 10am
that is when the curve indicates the begin of a change in the distance to home.
(e)
7.5 miles.
this is the point marked by a star on the graph.
down on the time scale this point shows 11:45am, and on the left side in the distance scale it shows 7.5 miles (the middle between 5 and 10 miles).
so, at that time she was still 7.5 miles away from home.
(f)
she traveled 40 miles to her grandmother (the left part of the curve from 0 distance until it turns flat), and then 40 miles back home (the right part of the curve from 40 distance all the way down to 0).
so, in total she traveled
40 + 40 = 80 miles