Question 451609
Tickets = -0.2x^2+12x+11 
set Tickets to 0 and solve for x:
0 = -0.2x^2+12x+11 
apply the "quadratic formula" to get:
x = {-0.9, 60.9}
throw out the negative solution leaving:
x = 60.9
solution: 61 days 
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Details of quadratic follows:
*[invoke quadratic "x", -0.2, 12, 11 ]