Answer:
70 Minutes
Step-by-step explanation:
Divide 25 into 50 to get 2 and then multiply 2 x 35 to get 70
Answer:
Radius =6.518 feet
Height = 26.074 feet
Step-by-step explanation:
The Volume of the Solid formed = Volume of the two Hemisphere + Volume of the Cylinder
Volume of a Hemisphere ![=\frac{2}{3}\pi r^3](https://tex.z-dn.net/?f=%3D%5Cfrac%7B2%7D%7B3%7D%5Cpi%20r%5E3)
Volume of a Cylinder ![=\pi r^2 h](https://tex.z-dn.net/?f=%3D%5Cpi%20r%5E2%20h)
Therefore:
The Volume of the Solid formed
![=2(\frac{2}{3}\pi r^3)+\pi r^2 h\\\frac{4}{3}\pi r^3+\pi r^2 h=4640\\\pi r^2(\frac{4r}{3}+ h)=4640\\\frac{4r}{3}+ h =\frac{4640}{\pi r^2} \\h=\frac{4640}{\pi r^2}-\frac{4r}{3}](https://tex.z-dn.net/?f=%3D2%28%5Cfrac%7B2%7D%7B3%7D%5Cpi%20r%5E3%29%2B%5Cpi%20r%5E2%20h%5C%5C%5Cfrac%7B4%7D%7B3%7D%5Cpi%20r%5E3%2B%5Cpi%20r%5E2%20h%3D4640%5C%5C%5Cpi%20r%5E2%28%5Cfrac%7B4r%7D%7B3%7D%2B%20h%29%3D4640%5C%5C%5Cfrac%7B4r%7D%7B3%7D%2B%20h%20%3D%5Cfrac%7B4640%7D%7B%5Cpi%20r%5E2%7D%20%5C%5Ch%3D%5Cfrac%7B4640%7D%7B%5Cpi%20r%5E2%7D-%5Cfrac%7B4r%7D%7B3%7D)
Area of the Hemisphere =![2\pi r^2](https://tex.z-dn.net/?f=2%5Cpi%20r%5E2)
Curved Surface Area of the Cylinder =![2\pi rh](https://tex.z-dn.net/?f=2%5Cpi%20rh)
Total Surface Area=
![2\pi r^2+2\pi r^2+2\pi rh\\=4\pi r^2+2\pi rh](https://tex.z-dn.net/?f=2%5Cpi%20r%5E2%2B2%5Cpi%20r%5E2%2B2%5Cpi%20rh%5C%5C%3D4%5Cpi%20r%5E2%2B2%5Cpi%20rh)
Cost of the Hemispherical Ends = 2 X Cost of the surface area of the sides.
Therefore total Cost, C
![=2(4\pi r^2)+2\pi rh\\C=8\pi r^2+2\pi rh](https://tex.z-dn.net/?f=%3D2%284%5Cpi%20r%5E2%29%2B2%5Cpi%20rh%5C%5CC%3D8%5Cpi%20r%5E2%2B2%5Cpi%20rh)
Recall: ![h=\frac{4640}{\pi r^2}-\frac{4r}{3}](https://tex.z-dn.net/?f=h%3D%5Cfrac%7B4640%7D%7B%5Cpi%20r%5E2%7D-%5Cfrac%7B4r%7D%7B3%7D)
Therefore:
![C=8\pi r^2+2\pi r(\frac{4640}{\pi r^2}-\frac{4r}{3})\\C=8\pi r^2+\frac{9280}{r}-\frac{8\pi r^2}{3}\\C=\frac{9280}{r}+\frac{24\pi r^2-8\pi r^2}{3}\\C=\frac{9280}{r}+\frac{16\pi r^2}{3}\\C=\frac{27840+16\pi r^3}{3r}](https://tex.z-dn.net/?f=C%3D8%5Cpi%20r%5E2%2B2%5Cpi%20r%28%5Cfrac%7B4640%7D%7B%5Cpi%20r%5E2%7D-%5Cfrac%7B4r%7D%7B3%7D%29%5C%5CC%3D8%5Cpi%20r%5E2%2B%5Cfrac%7B9280%7D%7Br%7D-%5Cfrac%7B8%5Cpi%20r%5E2%7D%7B3%7D%5C%5CC%3D%5Cfrac%7B9280%7D%7Br%7D%2B%5Cfrac%7B24%5Cpi%20r%5E2-8%5Cpi%20r%5E2%7D%7B3%7D%5C%5CC%3D%5Cfrac%7B9280%7D%7Br%7D%2B%5Cfrac%7B16%5Cpi%20r%5E2%7D%7B3%7D%5C%5CC%3D%5Cfrac%7B27840%2B16%5Cpi%20r%5E3%7D%7B3r%7D)
The minimum cost occurs at the point where the derivative equals zero.
![C^{'}=\frac{-27840+32\pi r^3}{3r^2}](https://tex.z-dn.net/?f=C%5E%7B%27%7D%3D%5Cfrac%7B-27840%2B32%5Cpi%20r%5E3%7D%7B3r%5E2%7D)
![When \:C^{'}=0](https://tex.z-dn.net/?f=When%20%5C%3AC%5E%7B%27%7D%3D0)
![-27840+32\pi r^3=0\\27840=32\pi r^3\\r^3=27840 \div 32\pi=276.9296\\r=\sqrt[3]{276.9296} =6.518](https://tex.z-dn.net/?f=-27840%2B32%5Cpi%20r%5E3%3D0%5C%5C27840%3D32%5Cpi%20r%5E3%5C%5Cr%5E3%3D27840%20%5Cdiv%2032%5Cpi%3D276.9296%5C%5Cr%3D%5Csqrt%5B3%5D%7B276.9296%7D%20%3D6.518)
Recall:
![h=\frac{4640}{\pi r^2}-\frac{4r}{3}\\h=\frac{4640}{\pi*6.518^2}-\frac{4*6.518}{3}\\h=26.074 feet](https://tex.z-dn.net/?f=h%3D%5Cfrac%7B4640%7D%7B%5Cpi%20r%5E2%7D-%5Cfrac%7B4r%7D%7B3%7D%5C%5Ch%3D%5Cfrac%7B4640%7D%7B%5Cpi%2A6.518%5E2%7D-%5Cfrac%7B4%2A6.518%7D%7B3%7D%5C%5Ch%3D26.074%20feet)
Therefore, the dimensions that will minimize the cost are:
Radius =6.518 feet
Height = 26.074 feet
The answer would be 30x-10
Answer:
first choice is the correct answer
Answer:
98.88
Step-by-step explanation:
I used a calculator and that's what it said the answer is srry if it might be wrong-