Answer:
Step-by-step explanation:
Given that a large mixing tank initially holds 400 gallons of water in which 70 pounds of salt have been dissolved. Pure water is pumped into the tank at a rate of 4 gal/min, and when the solution is well stirred, it is then pumped out at the same rate.
Let Q(t) be the quantity of salt at time t.
Q(0) = 70 pounds
Inflow of water = outflow = 4 gal/min
So resulting volume of tank at time t = 400 gallons
Rate of change of salt = inflow - outflow
= 0 - 
i.e. 
This is a variable separable equation
Use when t =0 Q = 70
A =70
So A(t) = Q(t) = 
and
A(0) = Q(0) = 70 lbs.
<h3>Whats your question?</h3>
16.5 degrees below the starting temp, whatever that is. If its 0, then -16.5 degrees.
The first equation would be (.5)5-11=-8.5, because the metal has been cooling for 5 hours.
The device that 'aids' in the cooling would be -5-3=-8, because it is a separate variable that cools the metal, so the amount the device cools is independent of the natural cooling amount, and the equation is independent of the natural cooling equation.
You then add -8.5 and -8, because the device has lowered 8.5 degrees and 8 degrees. This equals -16.5 degrees, or a decrease of 16.5 degrees.
Using proportions, supposing a scale of 1 inch = 3 feet, the actual measurements of her bed are given by: 9 ft x 18 ft.
<h3>What is a proportion?</h3>
A proportion is a fraction of a total amount, and equations can be built to find the desired measures in the problem using basic arithmetic operations such as multiplication or division, from the relations built in the problem.
One example of application of proportions is for scale problems, as the actual scale and the drawing length are compared to find the actual length of the object drawn.
In the context of this problem, the scale is given by:
1 inch = 3 feet.
The drawn length of the bed is given by:
3 inches x 6 inches.
Hence the actual length is given by:
9 feet x 18 feet.
As:
<h3>What is the missing information?</h3>
The scale of the drawing is missing, hence we are going to suppose that it is 1 inch = 3 feet.
More can be learned about proportions at brainly.com/question/24372153
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Total miles:350+150=500
Total hours:4+3=7
Avg speed:500/7=71.429 mph
