Final answer:
To find the number of repeat fans, we need to subtract the number of unique fans from the total number of tickets sold.
Step-by-step explanation:
To find the number of repeat fans, we need to subtract the number of unique fans from the total number of tickets sold. The venue's recent customer service reported that 60% of the tickets were sold to repeat fans.
So, we can calculate the number of repeat fans by multiplying 900 (total tickets sold) by 0.6 (percentage of repeat fans).
Number of repeat fans = 900 x 0.6 = 540
Therefore, there are 540 repeat fans attending the shows.