Answer:
15 miles
Step-by-step explanation:
Let
be the miles in the circular park path,
the time Louisa takes to finish and
the time Calvin takes to finish both in hours.
Then
, the longitude is equal to the velocity times the time used to finish. So


And the difference between Louisa's time and Calvin' time is 30 minutes, half an hour. So:

Three equations, three unknowns, the system can be solved.
Equalizing the equation with x :

In this last equation replace
with the other equation and solve:
With Louisa's time find x:
Answer:
66.666666666667% error
Step-by-step explanation:
Percent Error = Vobserved - Vtrue / Vtrue
= 9 - 27 / 27
= -18/27
= -66.666666666667%
= 66.666666666667% error
I hope this helps!