Answer:
He would gain by choosing air travel if, and only if, he values his time at more than $5 per hour.
Step-by-step explanation:
The problem states that:
A bus ticket from Washington to St. Louis costs $100, while it takes 32 hours to arrive.
A plane ticket from Washington to St. Louis costs $250, while it takes 2 hours to arrive.
Other things constant, Andrew would gain by choosing air travel if, and only if, he values his time at more than
If Andrew choses to go by plane, he saves 32-2 = 30 hours at the expense of $250-$100 = $150.
So, dividing the extra cost by the number of hours saved:
He would gain by choosing air travel if, and only if, he values his time at more than $5 per hour.