Answer:
$900
Step-by-step explanation:
you should only keep your ticket if you value seeing the musical at $900 which is the current value of the ticket that you hold or you can resell the ticket online/
The initial value of the ticket bought is $70 and the current vale of the ticket due to high demand is currently at $900. if you should sell the ticket you will make a profit of = 900 - 70 = $830. this profit would be massive compared to the purchase price
your economics professor would only advice you to take this action if you value seeing the musical for ≤ $900 else you should keep the ticket