The number of presale tickets sold is 271
Solution:
Let "p" be the number of presale tickets sold
Let "g" be the number of tickets sold at gate
Given that, total of 800 Pre-sale tickets and tickets at the gate were sold
Therefore,
Presale tickets + tickets sold at gate = 800
p + g = 800 ------ eqn 1
Given that, number of tickets sold at the gate was thirteen less than twice the number of pre-sale tickets
Therefore,
Number of tickets sold at gate = twice the number of pre-sale tickets - 13
g = 2p - 13 ------- eqn 2
Let us solve eqn 1 and eqn 2
Substitute eqn 2 in eqn 1
p + 2p - 13 = 800
3p -13 = 800
3p = 800 + 13
3p = 813
p = 271
Thus 271 presale tickets were sold