Question 877096
Base becomes (60-2x)(24-2x)
and since height will be x when the tabs are folded to meet forming the open rectangular form, the volume is x(60-2x)(24-2x).


{{{v=x(60*24-48x-120x+4x^2)}}}
{{{x(1440-168x+4x^2)}}}
{{{4x^3-168x^2+1440x}}}
Derivative is {{{12x^2-336x+1440}}}
{{{highlight_green(x^2-28x+120)}}}


Max or extreme volume will be where that derivative is 0.