Question 3 (12 points)
Gareth likes to talk on his cell phone. He has a plan in which he pays $40 a month
for 500 "free" minutes and then 5 cents a minute if he goes over.
Later that month, Gareth gets to the point where he has used 520 minutes. Tim
calls again. What would be the marginal cost of this five minute conversation?
$0.50
$40.00
$0.00
$0.25
