Question 346237
Let's see how long it takes to go 2 miles at 20mph
{{{Distance = Veloticy * Time}}}
{{{Distance/Velocity = Time}}}
{{{2/20 = 0.1}}} hours. So you would take 6 minutes to cover 2 miles at 20 mph

Now, how long did you take to go 1 mile at 10 mph

{{{Distance/Velocity = Time}}}
{{{1/10 = 0.1}}} hours . You used all 6 minutes on the first mile
Basically, you need to cover the next mile in no time at all.
So, either you go infinitely fast or it can't be done.
Since we can't go that fast, you cannot average 20 mph