Question 177184
Tickets =-0.2x^2+12x+11
--------------------------------------- 
{{{graph(400,300,-10,10,-10,20,-0.2x^2+12x +11)
------
[
b. Describe what happens to the tickets sales as time passes?
As x increases # of sales increase and then decrease.
-------------------------------------------
c. Use the quadratic equation to determine the last day that tickets will be sold. (Note: Write your answer in terms of the number of days after ticket sales begin.)
Determine when sales = zero:
-0.2x^2+12x+11 = 0

x = [-12 +- sqrt(144 -4*-0.2*11)]/[2*-0.2]

x = [-12 +- sqrt(152]/[-0.4]

Positive solution:
x = [-12 - 12.36]/[-.4]

x = [-24.36]/-0.4] = 60
Sales are 0 on day 60
Last day tickets will be sold will be day 59
==============================================
P.S. I made a typo on the earlier solution.
===================================================
Cheers,
Stan H>