We will have to use proportions:

Cross multiplying we get

Now divide:

Solve to tenths place we get

The woman casts a 36.6 ft long shadow.
A, D, E, and F are greater than -5
we can use formula

now, we can find a and b
Initially , price is 500
so,
At 


now, we can plug back

At 
we can use it and find b

now, we can solve for b
and we get

so,
annual depreciation rate is 27.144%.......Answer
<h3>
Answer: 8 miles</h3>
=======================================================
Work Shown:
x = number of miles
2x = cost of traveling x miles, at $2 per mile, without including the $3 fee
2x+3 = total cost now including the $3 entrance fee, without tip
2x+3+1 = total cost plus $1 tip
2x+4 = amount you spent
2x+4 = 20
2x = 20-4
2x = 16
x = 16/2
x = 8
You traveled 8 miles.