Question 1114283
{{{ N(x) = -.5x^2 + 11x + 115 }}}
If the form of the quadratic is:
{{{ y = a*x^2 + b*x + c }}}, then the
x-value of the
vertex ( peak in your case ) is at
{{{ x[v] = -b/(2a) }}}
{{{ a = -.5 }}}
{{{ b = 11 }}}
-------------------
{{{ x[v] = -11/(2*(-.5)) }}}
{{{ x[v] = 11 }}}
Now find {{{ N(11) }}}
{{{ N(11) = -.5*11^2 + 11*11 + 15 }}}
{{{ N(11) = 75.5 }}}


<U>Answer</U>.  Ticket sales will peak 11 days after concert was announced.
The peak price of the ticket will be $75.5.