Answer:
$7500
Explanation:
So to find mean the formula is total divided by no. of items or values so therefore the total no. of people is 310+390+380+420 which is 1500 people and if one ticket is $20 ,1500 tickets is 1500 multiplied by 20 which is $30,000 and the mean of one night would by 30,000 divided by 4 nights which is $7500 per night.Hope this helped!