Suppose that a large mixing tank initially holds 700 gallons of water in which 50 pounds of salt have been dissolved. another brine solution is pumped into the tank at a rate of 3 gal/min, and when the solution is well stirred, it is then pumped out at a slower rate of 2 gal/min. if the concentration of the solution entering is 4 lb/gal, determine a differential equation for the amount of salt a(t) in the tank at time t > 0. (use a for a(t).)

Answers

Answer 1
Final answer:

The differential equation for the amount of salt a(t) in the tank at time t > 0 is dA(t)/dt = 12 - 2A(t)/(35 + (3 - 2)t).

Explanation:

To find the differential equation for the amount of salt a(t) in the tank at time t > 0, we need to consider the rate of change of the salt concentration in the tank.

Let A(t) represent the amount of salt in the tank at time t. The salt entering the tank each minute is given by the concentration (4 lb/gal) multiplied by the rate of inflow (3 gal/min), which is 12 lb/min.

The salt leaving the tank each minute is given by the concentration in the tank (A(t)/V(t)) multiplied by the rate of outflow (2 gal/min), which is 2A(t)/(35 + (3 - 2)t).

Therefore, the rate of change of the salt in the tank is given by the difference between the rate of inflow and the rate of outflow: dA(t)/dt = 12 - 2A(t)/(35 + (3 - 2)t). This is our differential equation for the amount of salt in the tank.

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Related Questions

At a wedding​ reception, the bride and groom and five attendants will form a receiving line. How many ways can they be arranged in each of following​ cases? ​a) Any order will do. ​b) The bride and groom must be the last two in line. ​c) The groom must be last in line with the bride next to him.

Answers

A. In this case, they can be arranged at any order. Since there are 7 people all in all, therefore the number of arrangements is:

number of arrangements = 7P7 = 5040 ways

 

B. In this case, only the 5 people can be arranged in any order therefore 5P5. However the groom and bride can be interchanged on 2 places, therefore:

number of arrangements = 5P5 * 2 = 240 ways

 

C. In this case, only the 5 people can be arranged in any order while the groom and bride can no longer be interchanged, therefore:

number of arrangements = 5P5 = 120 ways

Final answer:

The arrangements for the wedding reception receiving line can be calculated using permutations: a) Any order will do, giving 7!, b) The bride and groom must be the last two in line, giving 5!, c) The groom must be last in line with the bride next to him, giving 6! x 2.

Explanation:

The question asks about the number of ways a bride and groom along with five attendants can be arranged in a receiving line at a wedding reception under different conditions. This is a permutations problem where we calculate the arrangements using factorial notation.

Case a: Any order will do.

In this case, we have a total of 7 people (bride, groom, and five attendants) who can be arranged in any order. The number of arrangements is the factorial of 7, which is calculated as 7! (7 factorial). So, the number of ways they can be arranged is 7! (which is 7 x 6 x 5 x 4 x 3 x 2 x 1 = 5,040 ways).

Case b: The bride and groom must be the last two in line.

Since the bride and groom's positions are fixed at the end of the line, we only need to arrange the five attendants. This is equivalent to 5! arrangements for the attendants. Thus, the number of ways they can be arranged is 5! (which is 5 x 4 x 3 x 2 x 1 = 120 ways).

Case c: The groom must be last in line with the bride next to him.

Here, the bride and groom are fixed in the last two positions, but the bride must be next to the groom. We consider the bride and groom as a single unit in addition to the five attendants. This gives us 6! arrangements for the attendants and the bride-groom unit, multiplied by 2 because the bride and groom can switch places within their unit. So, the number of ways they can be arranged is 6! x 2 (which is 6 x 5 x 4 x 3 x 2 x 1 x 2 = 1,440 ways).

Figure ABCD is a parallelogram. What is the value of n?
 3
 5
17
25

Answers

Opposite angles are euql therefore:-

2n + 32 = 4n - 2
34 = 2n 
n = 17 answer

Answer: the answer to this question is

choice c. 17

What is the markup for a pair of hiking boots that the store buys for $80 each if the markup rate is 15%?

Answers

Final answer:

To find the markup on a pair of hiking boots with a cost of $80 and a 15% markup rate, multiply the cost by 0.15 to get a $12 markup. The selling price would then be $80 + $12, totaling $92.

Explanation:

To calculate the markup for a pair of hiking boots that the store buys for $80 with a markup rate of 15%, first convert the percentage to a decimal by dividing by 100.

Markup rate as a decimal: 0.15

Next, multiply the cost price by the decimal.

Markup amount = Cost price × Markup rate

Markup amount = $80 × 0.15

Markup amount = $12

So, the markup on the hiking boots is $12. To find the selling price, you add the markup to the cost price:

Selling price = Cost price + Markup amount

Selling price = $80 + $12

Selling price = $92

The store would sell the hiking boots for $92.

What is the equation of the line that goes through (3,11) and is parallel to the line 2x-y=5

Answers

The equation is y=2x+5
why?
2x-y=5
y=2x-5
from here we can find the slope, which is 2, and we know that parallel lines have equal slopes
 the standard form of eq of line is y=mx+b
substitute y and x with the numbers from ordinate pair (3,11):
11=3*2+b
6+b=11
b=5
Now you can write the eq of line:
y=2x+5

Susan and Mark are standing at different places on a beach and watching a bird. The angles of elevation they make are 20º and 50º, respectively. If Susan and Mark are 7 kilometers apart and the bird is between them, the bird is at a height of kilometers from the ground. NextReset

Answers

The answer is 1.952 km

Answer:

The bird is at a height of 1.95 km from the ground.

Step-by-step explanation:

It is given that the distance between susan and mark is 7 km and bird is between  susan and mark. The angles of elevation they make are 20º and 50º, respectively.

Draw a perpendicular line from the bird on base.

Let the distance of susan from and the altitude be x.

In triangle ABS,

[tex]tan(20^{\circ})=\frac{AB}{x}[/tex]

[tex]tan(20^{\circ})x=AB[/tex]

[tex]0.364x=AB[/tex]       ..... (1)

In triangle ABM,

[tex]tan(50^{\circ})=\frac{AB}{7-x}[/tex]

[tex]1.192(7-x)=AB[/tex]     ..... (2)

From (1) and (2), we get

[tex]0.364x=1.192(7-x)[/tex]

[tex]1.556x=8342[/tex]

[tex]x=5.36[/tex]

The length of AB is,

[tex]AB=0.364(5.36)=1.95147\approx 1.95[/tex]

Therefore, the he bird is at a height of 1.95 km from the ground.

A student measured the lead content of a paint sample 4 times. the standard deviation of the measurements was found to be 1.1% of the average. can this student be 90% confident that the true value is within 1.8% of the measured average?

Answers

yes. 1.8% is 1.8/1.1 = 1.64 standard deviations from the mean. So looking at the table of standard deviation and confidences, I see for the 90% value a value of 1.644854Ď which is slightly higher than the computed value of 1.64. So yes, the student can be 90% confident that the true value is within 1.8% if the measured average.

For questions #6-8, use this data set and show your work  5, 10, 12, 4, 6, 11, 13, 5

Calculate the mean.
Type answer here

Calculate the median.
Type answer here

Calculate the mode.

Answers

mean (average) can be found by adding up all the numbers and then dividing that by how many numbers there are.
(5+10+12+4+6+11+13+5) / 8 = 66/8 = 8.25 <==

the mode (the number used most often) = 5....just so u know, there doesn't have to be a mode, and sometimes there is more then 1 mode. But for this one, the mode is 5. <==

median (the middle number)...for this, u put the numbers in order...
4,5,5,(6,10),11,12,13
now start moving from both ends going inward until u find the middle number...keep in mind, when u have an odd number of numbers, u will have 1 middle number.....but when there is an even number of numbers, like in this case, u will have 2 middle numbers...so u take ur 2 middle numbers, add them, then divide by 2 to get ur median.
median = (6 + 10) / 2 = 16/2 = 8 <==

Connor drives an an eighteen-wheeler. It cost Conner $456 to fill the truck up with diesel fuel. If diesel fuel cost $3 a gallon, how many gallons of fuel were bought?

Answers

152 because if you divide 456 by 3 you get 152
You just divide 456 by 3 which is 152gallons

(2.03)
Below are the steps to solve an equation:

Step 1: |x − 2| + 3 = 7
Step 2: |x − 2| = 7 − 3
Step 3: |x − 2| = 4

Which of the following is a correct next step to solve the equation? (1 point)

Answers

Given the definition of the absolute value function, there are two possibilities for the next step.

Rember that |x| = x when x is positive and |x| is - x when x is negative.

So, these are the two possibilities for |x - 2| = 4

1) When the content inside the absolute value is positive,  you can state x - 2 = 4

2) When the content inside the absolute value is negative  you can state x - 2 = - 4.

So, the answer is

x - 2 = 4 and x - 2 = - 4.

I found this list of choices for this question:

a. x + 2 = −4
b. −x − 2 = 4
c. x + 2 = 4
d. x − 2 = −4

In that list , the only right is x - 2 = - 4, so choose it.

Answer: option d. x - 2 = - 4


A coffeepot contains 1 1/2 quqarts of coffee. After Tonya pours an equal amount of coffee into two cups, 3 1/2 cups of coffee still remain in the pot. How much coffee did Tonya pour into each cup?

Answers

[tex]\bf 1\frac{1}{2}\implies \cfrac{1\cdot 2+1}{2}\implies \cfrac{3}{2}\quad \textit{now, how much is a quart of that?} \\\\\\ \cfrac{3}{2}\cdot \cfrac{1}{4}\implies \stackrel{of~coffee}{\cfrac{3}{8}}\impliedby makes\quad \stackrel{poured}{2cups}+\stackrel{remaining}{3\frac{1}{2}cups}\implies 5\frac{1}{2}~cups[/tex]

[tex]\bf \textit{now if }\frac{3}{8}\textit{ of coffee makes }5\frac{1}{2}\textit{ cups, how much in 1 cup?} \\\\\\ \cfrac{\quad \frac{3}{8}\quad }{5\frac{1}{2}}\implies \cfrac{\quad \frac{3}{8}\quad }{\frac{5\cdot 2+1}{2}}\implies \cfrac{\quad \frac{3}{8}\quad }{\frac{11}{2}}\implies \cfrac{3}{8}\cdot \cfrac{2}{11}\implies \stackrel{\textit{of coffee makes one cup}}{\cfrac{3}{44}}[/tex]

290 in expanded notation

Answers

This is the answer. 200 + 90 + 0

The place value chart can help us to write a number in expanded notation. When we put 290 into the place value chart, we can recognize that our number is equal to

2 hundreds + 9 tens + 0 units

Image is provided.

how do i solve 2 1/7 ÷ 1 1/4

Answers

First find the value of both mixed numbers as improper fractions.
2 1/7= 15/7.
1 1/4= 5/4

To divide fractions, multiply the first number by the reciprocal of the other. To multiply fractions, multiply the numerators and the denominators together.

(15/7)* (4/5) = 60/35

60/35= 12/7

Final answer: 12/7 or 1 5/7

Alan is 14 years old. This is twice as old as his brother James. How old is James?

Answers

Just divide 14 by two to find out how old James is.

James is 7.
alan=14

alan is twice as old as his brother
alan=2 times brother
14=2 times brother (james)
divide both sides by 2
7=brother (james)
james is 7 years old

There are two lakes in town of Roxbury. Lake Big Rock is 1650 ft longer than Little Lake Rock. Together, they are 5273 ft long. How long is each lake? Please show work.

Answers

They have already given you the length of the first lake so 3623 + 1650 = 5723
then then subtract 1650 form your answer which = 1973 so the first lake is 3623 ft long and the second is 1973 ft long. hope this helps.

Little Lake Rock is 1811.5 feet long, and Lake Big Rock is 3461.5 feet long.

Let's use algebra to solve this problem.

Let L be the length of Little Lake Rock in feet, and let B be the length of Lake Big Rock in feet.

We are given two pieces of information:

Lake Big Rock is 1650 ft longer than Little Lake Rock: B = L + 1650.

Together, they are 5273 ft long: B + L = 5273.

Now, we have a system of two equations with two variables:

B = L + 1650

B + L = 5273

We can use the first equation to express B in terms of L and then substitute this expression into the second equation:

B = L + 1650

Now, substitute B in the second equation:

(L + 1650) + L = 5273

Combine like terms:

2L + 1650 = 5273

Subtract 1650 from both sides:

2L = 5273 - 1650

2L = 3623

Now, divide by 2 to find the length of Little Lake Rock (L):

L = 3623 / 2

L = 1811.5 feet

Now that we know the length of Little Lake Rock, we can find the length of Lake Big Rock using the first equation:

B = L + 1650

B = 1811.5 + 1650

B = 3461.5 feet

So, Little Lake Rock is 1811.5 feet long, and Lake Big Rock is 3461.5 feet long.

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what is 8x-27-10-6x=15

Answers

8x-27-10-6x=15
2x-37=15
2x=15+37
2x= 52
x=26
First, simplify on the left side to get:
2x - 37 = 15
Then, add 37 to each side to get:
2x = 52
Lastly, divide each side by 2 to get:
x = 26

Hope this helps!! :)

Solve for A, 4(2a+3)=-3(a-1)+31

Answers

4(2a+3)=−3(a−1)+31
Step 1: Simplify both sides of the equation.4(2a+3)=−3(a−1)+31(4)(2a)+(4)(3)=(−3)(a)+(−3)(−1)+31(Distribute)8a+12=−3a+3+318a+12=(−3a)+(3+31)(Combine Like Terms)8a+12=−3a+348a+12=−3a+34Step 2: Add 3a to both sides.8a+12+3a=−3a+34+3a11a+12=34Step 3: Subtract 12 from both sides.11a+12−12=34−1211a=22Step 4: Divide both sides by 11.11a1/1=22/11
the answer is a=2

What is 45122 to the nearest ten thousand

Answers

50,000 so easy dudeeeee
45,122 round to the nearest thousand is 45,000 I hope this help you

Juanita is making necklaces to give as presents. She plans to put 15 beads on each necklace. Beads are sold in packages of 20. What is the least common number of packages she can buy to make necklaces and have no beads left over?

Answers

Hi there!

It should be 4 packages, with some mental math.

4 * 20 = 80

4 * 15 = 60

Remember we still have 20 beads left over now. Add it to 60 and bam! You're done!

Answer: 3

Step-by-step explanation:

Given : Juanita is making necklaces to give as presents.

She plans to put 15 beads on each necklace. Beads are sold in packages of 20.

To find the least common number of packages she can buy to make necklaces and have no beads left over,  First we need to find the least common multiple of 15 and 20.

Since , [tex]15=3\times5\\\\20=2\times2\times5[/tex]

Then least common multiple of 15 and 20 =[tex]2\times2\times3\times5=60[/tex]

Now, the least common number of packages she can buy to make necklaces and have no beads left over =[tex]\dfrac{60}{20}=3[/tex].

Hence, the least common number of packages she can buy to make necklaces and have no beads left over=3

What's the value of the 8's in 88,000

Answers

The value of the first 8 is ten thousand, and the value of the second 8 is one thousand. Hope this helps.
The value of the first 8 is ten thousand. :)

The nurse researcher is reading about linear regression. what is linear regression

Answers

Hello there.

   Linear regression is a useful tool that allows calculating approximate values for a function that passes through given points(with the best error possible). It is very useful in science to make an estimation of the comportment of movement, electricity and some decays.

   For example, I will relate a case in a physics lab: We calculated the positions of a car in an air rail and the times. With this information, I was able to make a linear regression to calculate the Position function for that case.
It is a linear approach for modeling the relationship between a scalar dependent variable and one or more explanatory variables denoted x.

You have a 5 question multiple choice test. Each question has four choices. You don’t know any of the answers. What is the experimental probability that you will guess exactly three out of five questions correctly?

Type your answer below using complete sentences.


Answers

This is an example of a binomial experiment or a Bernoulli trial.

p = 1/4. the probability of guessing a correct answer.
q = 1 - p = 3/4, the probability of guessing a wrong answer.

The probability of guessing 3 out of 5 questions is
[tex]_{5}C_{3} \,p^{3}q^{5-3} = \frac{5!}{3!2!}( \frac{1}{4})^{3}( \frac{3}{4})^{2} = 0.088[/tex]

Answer: 0.088

Factor the polynomial completely
24x^2y-6y

Answers

Divide by greatest common factor.
Answer simplified should be 6y(4x^2-1)
Rewrite in the form where a^2-b^2

Answer
6y(2x+1)(2x-1)

Agnes scored 87 on the first test 73 on the second test, 81 on the third test. supoise Agbes has one more test in the semester ajd wants to finish with a mean of at least 80. what does she need to get on her last test?

Answers

87+73+81+x=4*80, find x

867,000 rounded to the nearest hundred thousand

Answers

4 or below, keep it low, 5 or above give it a shove. The number ends in 67, so give it a shove up to 900,00 because it's asking for the nearest 100,000.

The table shows the cost of a ski rental package for a given number of people. People Cost ($) 4 160 5 200 6 240 7 280 The rate of change is constant in each table. Find the rate of change. Explain what the rate of change means for the situation. A. 1/40 dollars per room; the cost is $40 for each person. B. 40/1 dollars per person; the cost is $40 for each person. C. 1/280 dollars per person; the cost is $1 for 280 people. D. 160/1 dollars per person; the cost is $160 for each person.

Answers

Answer is -a-
Thanks (:

The answer is B. 40/1 dollars per person; the cost is $40 for each person.

is math related to science ?

Answers

yes because in science you use math to find the mass,volume,wight of an object. Math has everything to do with science. lol

The distance between Maggie’s home and her school is 5,280 yards. (Hint: 1 mile = 1,760 yards.)

Answers

Answer:

The answer is 10,560 yards and 6 miles. The 5,280 yards is just from her home to the school. So you multiply it by 2 and divide by 1760.

Step-by-step explanation:

Suppose you randomly select a letter from BURGER AND STARBIRD. Imagine writing these letters on Ping- Pong balls—one letter per ball—then putting them all in a barrel and remov- ing one. What is the probability of pulling out an R?

Answers

There are 17 possible letters you can choose from and 3 of them are "r"s. So, the probability is 3/17.

Hope this helps!

Multiply and simplify -12i x 3i

Answers

-36i^2 because -12 X 3= -36 and i X i = i^2
-12i×3i=-12×3×i×i
12×3=36 i×i=i²
So in the case of basic algebra, it's 36i²

If i is √-1 then i² is √-1×√-1 which is -1
36×-1=-36

Round 992,449 to the nearest hundred thousand

Answers

1,000,000 is your answer

hope this helps
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