Answer: You can travel 43 miles
Explanation:
To determine how far you can travel from the airport by taxi for $31.50, we can subtract the fixed charges from the total cost and then divide the remaining amount by the cost per mile.
Let's calculate:
$31.50 - $4.00 (base fare) - $6.00 (airport charge) = $21.50
Now, we can divide the remaining amount by the cost per mile:
$21.50 / $0.50 per mile = 43 miles
So, you can travel approximately 43 miles from the airport by taxi for $31.50.