Let
= amount of salt (in pounds) in the tank at time
(in minutes). Then
.
Salt flows in at a rate

and flows out at a rate

where 4 quarts = 1 gallon so 13 quarts = 3.25 gallon.
Then the net rate of salt flow is given by the differential equation

which I'll solve with the integrating factor method.



Integrate both sides. By the fundamental theorem of calculus,





After 1 hour = 60 minutes, the tank will contain

pounds of salt.
Answer: I wish I can help you, But I can't
Step-by-step explanation: lll
Answer: See explanation
Step-by-step explanation:
We are informed that Stephen rewrites 3r - 18 = 27 as 3(r - 6) = 3(9). This is quite thoughtful of Stephen and it's an easier way to solve the question.
In this case, 3 is a common factor to 3r, 18 and 27. Therefore, we will then have: 3(r - 6) = 3(9).
Since 3 is a common base to both, we are more concerned with the values inside the brackets. This will be:
r-6 = 9
r = 9 + 6
r = 15
Check: 3r - 18
3(15) - 18 = 45 - 18 = 27
Not sure but my guess would be the first one