Question 495764
I'm guessing that the problem is to find when is
most tickets are sold. This is because
the minus in front of the {{{ x^2 }}} term means
that the curve has a maximum and not a minimum.
The maximum occurs where
{{{ x = -b/(2a) }}}
{{{ a = -.2 }}}
{{{ b = 15 }}}
{{{-.2x^2 + 15x + 219 }}}
{{{ -b/(2a) = -15/(2*(-.2)) }}}
{{{ -b/(2a) = 37.5 }}}
Put this value of {{{x}}} back into
the equation to find maximum ticket sales
{{{-.2*37.5^2 + 15*37.5 + 219 }}}
{{{ -281.25 + 562.5 + 219 = 500.25 }}}
This must get rounded off to 500