Answer:
The answer is below
Step-by-step explanation:
Let Q represent the amount of salt in the tank at time t.
![\frac{dQ}{dt}= flow\ in - flow\ out\\ \\flow\ in=3\ gal/min*2\ lb/gal=6\ lb/min\\\\net\ gain\ in\ tank\ volume=3-4=-1, henceflow\ out= \frac{4Q}{100-t} \\\\\frac{dQ}{dt}= 6-\frac{4Q}{100-t} \\\\\frac{dQ}{dt}+ \frac{4Q}{100-t}=6\\\\The \ integrating\ factor\ is:\\\\IF=e^{\int\limits {\frac{4}{100-t} } \, dt }=e^{-4\int\limits {\frac{-1}{100-t}}=e^{-4ln(100-t)}=(100-t)^{-4}}\\\\Multiplying\ through \ by\ IF: \\\\(100-t)^{-4}\frac{dQ}{dt}+ (100-t)^{-4}\frac{4Q}{100-t}=6(100-t)^{-4}\\\\](https://tex.z-dn.net/?f=%5Cfrac%7BdQ%7D%7Bdt%7D%3D%20flow%5C%20in%20-%20flow%5C%20out%5C%5C%20%5C%5Cflow%5C%20in%3D3%5C%20gal%2Fmin%2A2%5C%20lb%2Fgal%3D6%5C%20lb%2Fmin%5C%5C%5C%5Cnet%5C%20gain%5C%20in%5C%20tank%5C%20volume%3D3-4%3D-1%2C%20henceflow%5C%20out%3D%20%5Cfrac%7B4Q%7D%7B100-t%7D%20%5C%5C%5C%5C%5Cfrac%7BdQ%7D%7Bdt%7D%3D%206-%5Cfrac%7B4Q%7D%7B100-t%7D%20%5C%5C%5C%5C%5Cfrac%7BdQ%7D%7Bdt%7D%2B%20%5Cfrac%7B4Q%7D%7B100-t%7D%3D6%5C%5C%5C%5CThe%20%5C%20integrating%5C%20factor%5C%20is%3A%5C%5C%5C%5CIF%3De%5E%7B%5Cint%5Climits%20%7B%5Cfrac%7B4%7D%7B100-t%7D%20%7D%20%5C%2C%20dt%20%7D%3De%5E%7B-4%5Cint%5Climits%20%7B%5Cfrac%7B-1%7D%7B100-t%7D%7D%3De%5E%7B-4ln%28100-t%29%7D%3D%28100-t%29%5E%7B-4%7D%7D%5C%5C%5C%5CMultiplying%5C%20through%20%20%5C%20by%5C%20IF%3A%20%5C%5C%5C%5C%28100-t%29%5E%7B-4%7D%5Cfrac%7BdQ%7D%7Bdt%7D%2B%20%28100-t%29%5E%7B-4%7D%5Cfrac%7B4Q%7D%7B100-t%7D%3D6%28100-t%29%5E%7B-4%7D%5C%5C%5C%5C)
![Integrating:\\\\A(100-t)^{-4}=-2(100-t)^{-3}+c\\\\A=-2(100-t)+\frac{c}{(100-t)^{-4}} \\\\at, t=0,A=0\\\\0=-2(100-0)+\frac{c}{(100-0)^{-4}}\\\\c=0.02\\\\A=-2(100-t)+\frac{0.02}{(100-t)^{-4}}](https://tex.z-dn.net/?f=Integrating%3A%5C%5C%5C%5CA%28100-t%29%5E%7B-4%7D%3D-2%28100-t%29%5E%7B-3%7D%2Bc%5C%5C%5C%5CA%3D-2%28100-t%29%2B%5Cfrac%7Bc%7D%7B%28100-t%29%5E%7B-4%7D%7D%20%5C%5C%5C%5Cat%2C%20t%3D0%2CA%3D0%5C%5C%5C%5C0%3D-2%28100-0%29%2B%5Cfrac%7Bc%7D%7B%28100-0%29%5E%7B-4%7D%7D%5C%5C%5C%5Cc%3D0.02%5C%5C%5C%5CA%3D-2%28100-t%29%2B%5Cfrac%7B0.02%7D%7B%28100-t%29%5E%7B-4%7D%7D)
Answer:
X=120
X=54
Step-by-step explanation:
(this is for the top one and the one below the top one)
(I think they are right)
The answer is 6 because you do this
1/3 of 18 divide 18 by 3 amd get 6
Given:
![(ax+2)(bx+7)=15x^2+cx+14](https://tex.z-dn.net/?f=%28ax%2B2%29%28bx%2B7%29%3D15x%5E2%2Bcx%2B14)
And
![a+b=8](https://tex.z-dn.net/?f=a%2Bb%3D8)
Required:
To find the two possible values of c.
Explanation:
Consider
![\begin{gathered} (ax+2)(bx+7)=15x^2+cx+14 \\ abx^2+7ax+2bx+14=15x^2+cx+14 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20%28ax%2B2%29%28bx%2B7%29%3D15x%5E2%2Bcx%2B14%20%5C%5C%20abx%5E2%2B7ax%2B2bx%2B14%3D15x%5E2%2Bcx%2B14%20%5Cend%7Bgathered%7D)
So
![\begin{gathered} ab=15-----(1) \\ 7a+2b=c \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20ab%3D15-----%281%29%20%5C%5C%207a%2B2b%3Dc%20%5Cend%7Bgathered%7D)
And also given
![a+b=8---(2)](https://tex.z-dn.net/?f=a%2Bb%3D8---%282%29)
Now from (1) and (2), we get
![\begin{gathered} a+\frac{15}{a}=8 \\ \\ a^2+15=8a \\ \\ a^2-8a+15=0 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20a%2B%5Cfrac%7B15%7D%7Ba%7D%3D8%20%5C%5C%20%20%5C%5C%20a%5E2%2B15%3D8a%20%5C%5C%20%20%5C%5C%20a%5E2-8a%2B15%3D0%20%5Cend%7Bgathered%7D)
![a=3,5](https://tex.z-dn.net/?f=a%3D3%2C5)
Now put a in (1) we get
![\begin{gathered} (3)b=15 \\ b=\frac{15}{3} \\ b=5 \\ OR \\ b=\frac{15}{5} \\ b=3 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20%283%29b%3D15%20%5C%5C%20b%3D%5Cfrac%7B15%7D%7B3%7D%20%5C%5C%20b%3D5%20%5C%5C%20OR%20%5C%5C%20b%3D%5Cfrac%7B15%7D%7B5%7D%20%5C%5C%20b%3D3%20%5Cend%7Bgathered%7D)
We can interpret that either of a or b are equal to 3 or 5.
When a=3 and b=5, we have
![\begin{gathered} c=7(3)+2(5) \\ =21+10 \\ =31 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20c%3D7%283%29%2B2%285%29%20%5C%5C%20%3D21%2B10%20%5C%5C%20%3D31%20%5Cend%7Bgathered%7D)
When a=5 and b=3, we have
![\begin{gathered} c=7(5)+2(3) \\ =35+6 \\ =41 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20c%3D7%285%29%2B2%283%29%20%5C%5C%20%3D35%2B6%20%5C%5C%20%3D41%20%5Cend%7Bgathered%7D)
Final Answer:
The option D is correct.
31 and 41
Answer:
2.50000 or 2.5 or 2 1/2
Step-by-step explanation:
You have the number 250,000. you have to get the decimal between 1.00 and 10.00 to do this we are going to move the decimal over left one at a time.
25,000.0
2,500.00
250.000
25.0000 25 is really close but not between 1 and 10 so were going to move the decimal one more time
2.50000
2.50000 is between 1 and 10 so its the anwser we are looking for.