Final answer:
The variable cost per guest-day is $0.75.
Step-by-step explanation:
The variable cost per guest-day can be calculated by finding the change in cost and dividing it by the change in activity level.
Change in cost = High activity level cost - Low activity level cost = $13,500 - $7,500 = $6,000.
Change in activity level = High activity level - Low activity level = 12,000 - 4,000 = 8,000.
Variable cost per guest-day = Change in cost / Change in activity level = $6,000 / 8,000 = $0.75 per guest-day.
Therefore, the correct answer is option 1) 0.75 per guest-day.