Answer:
Step-by-step explanation:
The given function is
We need to find first partial derivatives of the function.
Differentiate partially w.r.t. x and y, z are constants.
Differentiate partially w.r.t. y and x, z are constants.
Differentiate partially w.r.t. z and x, y are constants.
Therefore, the first partial derivatives of the function are 
.
The first bag would be 5.34$ and the second would be 5.53$ and the second bag is better cause your only spending 19 more cents for 1.5 more pounds
I think maybe it's A. sorry if that's wrong
40/100=34/x
40x=3400
x=3400/40
x=85
Check the picture below.
so the lunchbox is really a semi-circle with a radius of 3, sitting on top of a square of 6x6, with a lenght of 10.
the volume of the lunchbox then will be the area of the semi-circle and square times the length.
![\bf \left[ \stackrel{\textit{semi-circle's area}}{\frac{\pi 3^2}{2}}+\stackrel{\textit{square's area}}{(6\cdot 6)} \right]\stackrel{length}{10}\implies \left( \frac{9\pi }{2}+36\right)(10)](https://tex.z-dn.net/?f=%5Cbf%20%5Cleft%5B%20%5Cstackrel%7B%5Ctextit%7Bsemi-circle%27s%20area%7D%7D%7B%5Cfrac%7B%5Cpi%203%5E2%7D%7B2%7D%7D%2B%5Cstackrel%7B%5Ctextit%7Bsquare%27s%20area%7D%7D%7B%286%5Ccdot%206%29%7D%20%5Cright%5D%5Cstackrel%7Blength%7D%7B10%7D%5Cimplies%20%5Cleft%28%20%20%5Cfrac%7B9%5Cpi%20%7D%7B2%7D%2B36%5Cright%29%2810%29)
