Harry gave away 3/6, or half of the brownies
1/6 plus 2/6 equals 3/6
-3 and 4......................
41 and 1/5 miles.
You can get this by multiplying the distances by number of days. Then add the two together.
Recall your d = rt, distance = rate * time
thus

notice, the first car leaves at "x" time, the other leaves on hour later, or x + 1
the first car travels some distance "d", whatever that is, thus
the second car, picks up the slack, or the difference, they're 380 miles
apart, thus the difference is 380-d