Answer:
9
Step-by-step explanation:
Start with the total amount Dan paid and subtract the part of the payment that is for the ticket.
450-315=135
Assuming that all of that $135 was for luggage fees and each pound over the limit costs $15, then the question is, how many times did Dan pay $15 until he'd paid the full $135 luggage fee.
So divide $135 by $15.
135/15=9
So his luggage weighted 59 pounds, which is 9 pounds over the limit.