So let's start out by labeling Ethan as X
Since 85 is 1/3 of what Ethan drove, that means Ethan drove 3 times of 85.
85= (3x) -21
85 -21 = 3x
60=3x
20 = x
16/21 is your answer
You can take a 2 out of both numbers to get your answer
I hope this helped! :)
there is not enough info given to tell how long it would take
