Answer:
, 
Step-by-step explanation:
The equations of volume and surface area are presented below:


The length of the tank is:

The expression fo the surface area is therefore simplified into an univariable form:


The first and second derivatives of the expression are, respectively:


The first derivative is equalized to zero and length of the square side is now found:



![l = \sqrt[3]{\frac{138}{4} }](https://tex.z-dn.net/?f=l%20%3D%20%5Csqrt%5B3%5D%7B%5Cfrac%7B138%7D%7B4%7D%20%7D)

Now, the second derivative offers a criteria to determine if solution leads to an absolute minimum:

(Absolute minimum)
The depth of the tank is:


20 • 3=60, 25 • 4=100. 60+100=160. 160-10=150. Josie makes $150.
Answer:
she purchased 6 compact discs
Step-by-step explanation:
13.95 × 6 + 1.95= 85.65
9514 1404 393
Answer:
123.6 m²
Step-by-step explanation:
The area is given by the formula ...
A = (AB)(AD)sin(∠A)
A = (7 m)(20 m)sin(62°) ≈ 123.6 m²