Answer: 2,100 tickets
Explanation:
105 people have arrived for the concert yet it is said that 95% of people are yet to arrive. This means that the 105 people are 5% of the tickets sold.
Assume the total number of tickets sold is x:
5% * x = 105
0.05x = 105
x = 105 / 0.05
x = 2,100 tickets