Answer:
Step-by-step explanation:
Volume of tank is 3000L.
Mass of salt is 15kg
Input rate of water is 30L/min
dV/dt=30L/min
Let y(t) be the amount of salt at any time
Then,
dy/dt = input rate - output rate.
The input rate is zero since only water is added and not salt solution
Now, output rate.
Concentrate on of the salt in the tank at any time (t) is given as
Since it holds initially holds 3000L of brine then the mass to volume rate is y(t)/3000
dy/dt= dV/dt × dM/dV
dy/dt=30×y/3000
dy/dt=y/100
Applying variable separation to solve the ODE
1/y dy=0.01dt
Integrate both side
∫ 1/y dy = ∫ 0.01dt
In(y)= 0.01t + A, .A is constant
Take exponential of both side
y=exp(0.01t+A)
y=exp(0.01t)exp(A)
exp(A) is another constant let say C
y(t)=Cexp(0.01t)
The initial condition given
At t=0 y=15kg
15=Cexp(0)
Therefore, C=15
Then, the solution becomes
y(t) = 15exp(0.01t)
At any time that is the mass.
I feel like it’s d because it is changed to the other form
Answer:

Step-by-step explanation:
Assuming this complete problem: "A cell tower is located at (-8, 4) and transmits a circular signal that covers three major cities. The three cities are located on the circle and have the following coordinates: G (-4, 7), H (-13, 4), and I (-8, -1). Find the equation of the circle"
For this case the generla equation for the circle is given by:

From the info we know that the tower is located at (-8, 4) so then h = -8 and k = 4, so then we need to find the radius. So we have the equation like this:
If the 3 points are on the circle then satisfy the equation. We can use the first point (-4,7) and if we replace we can find the value for 

So then 
And if we replace the second point we got this:

And for the third point we have:

And we got the same result.
So then our final equation is given:

Answer:
Step-by-step explanation:
A graph has a constant of proportionality of 7.2. Let y represent minutes and x represent miles.
What is the unit rate of the relationship?
Enter your answer, as a decimal, in the box
min/mi
pls help me
Answer:
3. x = y - 3
Step-by-step explanation:
You want to move all numbers on the same side of x to the other side with y. Whenever doing this, we have to reverse the operation. In this problem, we have + 3 with x. So we will need to subtract 3 from both sides.
x + 3 = y
x = y - 3