SOLUTION: On a 2 mile racetrack you bike the first mile at 10 mph. At what rate must you bike the second mile in order to average 20mph for the entire track? I am not sure what formula to

Question 346237: On a 2 mile racetrack you bike the first mile at 10 mph. At what rate must you bike the second mile in order to average 20mph for the entire track?
I am not sure what formula to use and the average has me confused.
Found 2 solutions by vleith, Fombitz:
Answer by vleith(2983) (Show Source): You can put this solution on YOUR website!
Let's see how long it takes to go 2 miles at 20mph

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

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
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
Rate*Time=Distance
.
.
.
Average speed equals total distance divided by total time.
.
.
For the first mile,

For the second mile,

The total distance is 2 miles.
The total time is
.
.
.

There is no solution.
You cannot go fast enough to average 20 mph.
20 mph for a 2 mile track requires 1/10 hr.
You already used that 1/10 hr for your first lap.

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