ANSWER
271 pre-sale tickets were sold.
EXPLANATION
Let p represent the number of pre-sale tickets and t represent the number of tickets sold.
According to the question,a total of 800 pre-sale tickets and tickets were sold .
This implies that,
[tex]p + t = 800[/tex]
Also the number of tickets sold is 13 less than twice the number of pre-sale tickets.
This gives another equation:
[tex]t = 2p - 13[/tex]
We substitute, the second equation into the first equation to obtain:
[tex]p + 2p - 13 = 800[/tex]
This implies that;
[tex]3p = 813[/tex]
Divide both sides by 3
[tex]p = \frac{813}{3} = 271[/tex]
Hence 271 pre-sale tickets were sold.
