When the surrounding flaps are folded up, the base of the box will have dimensions
by
, and the box will have a height of
. So the box has volume, as a function of
,
![V(x)=(11-2x)(16-2x)x=176x-54x^2+4x^3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xedf30f4l2kk9omdyisx2ajvem5ogjym5r.png)
I don't know what technology is available to you, but we can determine an exact value for
that maximizes the volume by using calculus.
Differentiating
with respect to
gives
![(\mathrm dV)/(\mathrm dx)=176-108x+12x^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/g7tkrzbdq415dn515ieawn84osunxl3pfz.png)
and setting this equal to 0 gives two critical points at
![x=\frac{27\pm√(201)}6\implies x\approx2.1\text{ or }x\approx6.9](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qnxd9fp6fi8j4d3lrzg31u0ec7lzrbyrpg.png)
For the larger critical point we would get a negative volume, so we ignore that one. Then the largest volume would be about 168.5 cubic in.