Let x(t) denote the amount of salt (in kg) in the tank at time t. The tank starts with 18 kg of salt, so x (0) = 18.
The solution is drained from the tank at a rate of 90 L/min, so that the amount of salt in the tank changes according to the differential equation
dx(t)/dt = - (x(t) kg)/(9000 L) × (90 L/min) = -1/100 x(t) kg/min
or, more succintly,
x' = -1/100 x
This equation is separable as
dx/x = -1/100 dt
Integrating both sides gives
∫ dx/x = -1/100 ∫ dt
ln|x| = -1/100 t + C
x = exp(-1/100 t + C )
x = C exp(-t/100)
(a) Using the initial condition x (0) = 18, we find
18 = C exp(0) ==> C = 18
so that
x(t) = 18 exp(-t/100)
(b) After 20 minutes, we have
x (20) = 18 exp(-20/100) = 18 exp(-1/5) ≈ 14.74
so the tank contains approximately 14.74 kg of salt after this time.
A rectangle auditorium seats 1260 people. The number of seats in each row exceeds the number of rows by 12. Find the number of seats in each row
Answer:
Easy, all you ha
Step-by-step explanation:
Can you please help me
Answer:
Step-by-step explanation:
⅝ - 5/9 = 5/72
What is the total cost of a $28 pair of jeans if the sales tax is 7.5%?
Answer:
30.10
Step-by-step explanation:
First find the amount of tax
28 * 7.5%
28 * .075
2.10
Add this to the price of the pants
28+2.10 =30.10
Expand (2+x)^-3
....
Answer:
1/(x^3 + 6x^2 + 12x + 8)
Step-by-step explanation:
The first thing we do is rationalize this expression. (2+x)^-3 is written as
1/(2+x)^3
Then from there we can foil out the denominator. It is easiest to foil (2+x)(2+x) first and then multiply that product by (2+x).
(2+x)(2+x) = 4 + 4x + x^2
(4+4x+x^2)(2+x) = 8+8x+2x^2+4x+4x^2+x^3.
Then we combine like terms and put them in order to get:
x^3 + 6x^2 + 12x + 8
And of course we can't forget that this was raised to the negative third power, so our answer is 1/(x^3 + 6x^2 + 12x + 8)
Answer:
Hello,
Step-by-step explanation:
[tex](a+x)^n=a^n+\left(\begin{array}{c}n\\ 1\end{array}\right)*a^{n-1}*x+\left(\begin{array}{c}n\\ 2\end{array}\right)*a^{n-2}*x^2+\left(\begin{array}{c}n\\ 3\end{array}\right)*a^{n-3}*x^3+\left(\begin{array}{c}n\\ 4\end{array}\right)*a^{n-4}*x^4+...+\left(\begin{array}{c}n\\ n\end{array}\right)*a^{n-n}*x^n[/tex]
[tex]with \\\\\left(\begin{array}{c}n\\ 1\end{array}\right)=n\\\\\left(\begin{array}{c}n\\ 2\end{array}\right)=\dfrac{n(n-1)}{2!} \\\\\left(\begin{array}{c}n\\3 \end{array}\right)=\dfrac{n(n-1)(n-2)}{3!} \\\\...\\[/tex]
[tex]\dfrac{1}{(2+x)^3} =\dfrac{1}{8} +3*\dfrac{x}{4}+3\dfrac{x^2}{2}+x^3\\\\[/tex]
14. The area of 10 square plots is 160 ares. Find the length in metres of the side of each plot (3mks)
Answer:
Step-by-step explanation:
1 are = 100 m²
Assuming the ten squares are congruent, the area of each square is 160/10 = 16 are
16 are × 100 m²/are = 1600 m²
each side is √1600 = 40 m
The length of side of plot is 40 meters.
What is area?The total space occupied by a flat (2-D) surface or shape of an object is known as area.
Draw a square on a piece of paper with a pencil. It has two dimensions. The term "area" refers to the area that the shape occupies on the paper.
Now picture your square as being comprised of smaller unit squares. The number of unit squares required to cover a 2-D shape's total surface area is used to calculate its area.
Given the area of 10 square plot is 160 are,
here 1 are = 100 m²
area of 10 square plot = 160 x 100 = 16,000 m²
area of 1 square plot = 16000/10 = 1600 m²
area of square is "a²"
where a is side of square
area = a² = 1600 m²
a = √1600
a = 40 m
Hence the length of side of each plot is 40 meters.
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Algebra II Part 1
On your paper, graph these coordinates:
(-1, 1), (-5, 2)
Type the correct equation of the line.
Note: Do not use fractions in your answer.
Answer:
4y+x-3=0
Step-by-step explanation:
The equation is y=mx+b
1) Use the coordinates from the first point
(-1,1)
1= -m+b
2) Use the coordinates frm the second point
(-5,2) (y=mx+b, use x=-5, y=2)
2=-5m+b
You have the system of equations
1=-m+b (multiply by -1) -1= m-b
2=-5m+b
Add the first equation (multiplied by -1) and the second one
-1+2= m-b-5m+b
1= -4m
m=-0.25
2=1.25+b
b=0.75
y=-0.25x+0.75
4y= -x+3
4y+x-3=0
What is the value of the expression, written in standard form?
Answer:
200
Step-by-step explanation:
6.6/3.3 = 2
10^-2 - (-4) = 10^2
The answer is 2 * 10^2 or 200.
What sum of money, invested at 9%
interest per year, is needed to provide an
income of $45 per year?
Answer:
$500
Step-by-step explanation:
Intrest = P. A * Intrest Rate * Time
Time = 1 year, Intrest Rate = 9%, P. A. is what we need to find, Intrest is 45
45=x*9/100*1, x=500
Answer:
500
Step-by-step explanation:
I = PRT where I is the interest, P is the amount invested, R is the rate and T is the time
We want 1 year at 9% to get 45 dollars in interest
45 = P ( .09) (1)
45 = .09P
Divide each side by .09
45/ .09 = P
500 =P
help pls!!! Classify the following question: “President, vice president, and secretary are being chosen for the Environmental Club. In how many different ways can these three offices be filled from a list of ten members?”
the answer is: combation
How many solutions on the interval {0, 2020} sin 2x + 1 + sin x + cos x have?
Answer:
0
Step-by-step explanation:
[tex] \frac{2}{4} + 5 \times 36 + 2 \frac{6}{3 } = [/tex]
what is answer
Step-by-step explanation:
[tex] \frac{2}{4} + 5 \times 36 + 2 \frac{6}{3} [/tex]
[tex] = \frac{1}{2} + 180 + 2 \times \frac{2}{1} [/tex]
[tex] = \frac{1}{2} + 180 + 4[/tex]
[tex] = \frac{1 + 360 + 8}{2} [/tex]
[tex] = \frac{369}{2} [/tex]
[tex] = 184 \frac{1}{2} \: or \: 184.5(ans)[/tex]
Find the lengths of the other two sides of the isosceles right triangle
Answer:
h²=p²+b²
(7√2)²=x²+x²
(49×2)=2x²
2x²=49ײ
x²=49×2/2
x²=49
x=√49=7
x=7
OAmalOHopeO
Which of the following is equivalent to 0 equals 3 x squared minus 12 x minus 15 when completing the square?
After completing the square the quadratic equation [tex]3x^{2} -12x-15=0[/tex] is equivalent to [tex](x-2)^2=3^2[/tex].
What is a quadratic equation?"It is a polynomial equation with degree two."
What is completing the square method?"It is a method that is used for converting a quadratic expression of the form [tex]ax^2 + bx + c[/tex] to [tex]a(x - h)^2 + k[/tex] "
For given example,
We have been given a quadratic equation.
[tex]3x^{2} -12x-15=0[/tex]
First we divide above quadratic equation by 3,
[tex]x^{2} -4x-5=0\\\\x^2-4x=5[/tex] ................(i)
Now for completing the square first find [tex](\frac{-b}{2a} )[/tex]
[tex]\frac{-b}{2a}\\=\frac{-(-4)}{(2)(1)}\\\\ =\frac{4}{2}\\\\ =2[/tex]
Add [tex](\frac{-b}{2a} )^2[/tex] on both the sides of equation (i),
[tex]x^{2} -4x+4=5+4\\\\(x-2)^2=9\\\\(x-2)^2=3^2[/tex]
Therefore, after completing the square the quadratic equation [tex]3x^{2} -12x-15=0[/tex] is equivalent to [tex](x-2)^2=3^2[/tex].
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Can someone check my answers if they are correct or incorrect? If it is incorrect, please let me know why it is incorrect please.
Find the probability. A calculator requires a keystroke assembly and a logic circuit. Assume that 75% of the keystroke assemblies and 94% of the logic circuits are satisfactory. Find the probability that a finished calculator will be satisfactory.
Answer:
0.705 = 70.5% probability that a finished calculator will be satisfactory.
Step-by-step explanation:
Probability of independent events:
If two events, A and B, are independent, the probability of both happening is the multiplication of the probabilities of each happening, that is:
[tex]P(A \cap B) = P(A)P(B)[/tex]
In this question:
Event A: Keystroke assembly are satisfactory.
Event B: Logic circuits are satisfactory.
75% of the keystroke assemblies and 94% of the logic circuits are satisfactory.
This means that [tex]P(A) = 0.75, P(B) = 0.94[/tex]
Find the probability that a finished calculator will be satisfactory.
Both satisfactory, and since they are independent:
[tex]P(A \cap B) = P(A)P(B) = 0.75*0.94 = 0.705[/tex]
0.705 = 70.5% probability that a finished calculator will be satisfactory.
Write the phrase as an algebraic expression: 3 less than 4 times a number
Answer:
4x-3 is the expression to your question
Answer:
3[tex]\leq[/tex]4x
Step-by-step explanation:
FX) is defined by the equation f(x) = 4x2 - 2x +17. What effect will multiplying
f(x) by 0.5 have on the graph?
A. The graph will be stretched horizontally.
B. The graph will be compressed horizontally.
C. The graph will be stretched vertically.
D. The graph will be compressed vertically.
Step-by-step explanation:
the graph will be compressed vertically
Choose the correct answer.
The History Activities were about ___ and ___. They were both from ___. One of them had a ___ named after him. The other had a ___ named after him. The work they did together on a problem they got from a ___ laid the foundation for probability theory.
A. Pascal, Decartes, England, graph, book, relative
B. Luniz, Kolmogrov, Germany, church, square, teacher
C. Fermat, Luniz, England, law, diagram, priest
D. Pascal, Fermat, France, triangle, theorem, gambler
Answer:
I say Its letter d
Step-by-step explanation:
I hope this help
Which of the following is a quadratic function
A quadratic a function has a form of,
[tex]f(x)=ax^2+bx+c,a\neq0[/tex]
The first function has a term [tex]x^3[/tex] which doesn't fit the profile of a quadratic function. The highest exponent on x inside a quadratic function can be 2, but here we have 3 so this is not a quadratic function, but rather a cubic function.
The second function fits the form of a quadratic function perfectly.
The third function is a bit tricky. While technically the third function could be considered quadratic if the leading term would be something like [tex]0x^2[/tex] and we did't even see it written out because multiplying with 0. But when we specified the form of a quadratic function, we strictly said that the number before [tex]x^2[/tex] aka [tex]a[/tex] cannot equal to zero. So the last function is not a quadratic function but rather a linear function.
Hope this helps :)
Step-by-step explanation:
f(x) = 4x² + x - 3
[tex]f(x) = 4x {}^{2} + 3 - 2[/tex]
r3t40 is correct
In 20P4 how many choices are
there for vice-president from a
state of four officers?
Note: The vice president is the second officer
to be elected.
Acellus
Explanation:
There are 20 choices for president, and 20-1 = 19 choices for vice president. You count down by 1 each time you fill a seat. So that means you'll have 19-1 = 18 choices for the third seat, and 18-1 = 17 choices for the fourth seat.
Instructions are in the picture
Answer:
123123 3213123 12312 dasdsd aw dasd sda asdasd
Step-by-step explanation:
Which of the following are exterior angles? Check all that apply.
Answer:
<5
Step-by-step explanation:
exterior angles + the corresponding interior angle of the triangle = 180º or a straight angle
the only exterior angle shown in the diagram is <5, which corresponds to the interior <2
hope this helps!
Answer:
<5
Step-by-step explanation:
everything else is matched up perfectly so it has to be <5
Assume that two marbles are drawn without replacement from a box with 1 blue, 3 white, 2 green, and 2 red marbles. Find the probability that the first marble is white and the second marble is blue.
Answer:
3/56
Step-by-step explanation:
Probability is the ratio of the number of possible outcome to the number of total outcome.
Given that two marbles are drawn without replacement from a box with 1 blue, 3 white, 2 green, and 2 red marbles.
The total number of marbles in the box
= 1 + 3 + 2 + 2
= 8 marbles
The probability that the first marble is white and the second marble is blue
= 3/8 * 1/7
= 3/56
f(x) = x - 1. Find the inverse of f(x).
Answer:
f^-1 (x) = x+1
Step-by-step explanation:
f(x) = x-1
y = x-1
Exchange x and y
x = y-1
Solve for y
Add 1 to each side
x+1 = y-1+1
x+1 = y
The inverse is x+1
f^-1 (x) = x+1
Can someone please help me
Researchers would like to assess the overall health of white pine trees in a state park. Which of the following
methods for choosing the trees to assess would be considered a convenience sample?
O A ranger hires employees to assess every tree in the park.
O The 100 trees closest to a ranger station are assessed for damage.
O Agrid map of the park is used, and 100 random points on the grid are chosen and used to select the trees to
assess
O Each tree in the state park is tagged with a number, and 100 random numbers that represent the trees are
selected and assessed for damage.
Answer:
The 100 trees closest to a ranger station are assessed for damage.
Step-by-step explanation:
Convenience samples are samples taken from only around the focal point.
Option B is correct, The 100 trees closest to a ranger station are assessed for damage.
What is Statistics?Statistics is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data.
A convenience sample is a non-random method of sampling that involves selecting subjects that are easy to access or readily available.
Of the methods listed, the convenience sample is the one where the trees are selected based on their proximity to a ranger station:
The 100 trees closest to a ranger station are assessed for damage.
This method is a convenience sample because it does not involve random selection of trees.
Instead, the trees are chosen based on their proximity to a specific location.
This can introduce bias into the sample, as trees near the ranger station may not be representative of the overall health of white pine trees in the state park.
Hence, Option B is correct, The 100 trees closest to a ranger station are assessed for damage.
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Instructions: Find the area of the trapezoid
and round to the nearest tenth.
10.2 mi.
7 mi.
4.2 mi.
Area:
mi?
Answer:
299.88 mi. !!!!!
you just multiple all of them together to get the area!!!
Fewer and fewer customers have been coming into the restaurant, so Bill, the manager, decides to change the entire menu. After he does this, he finds out that people loved the food, but the service has been driving people away. This represents what kind of problem in the decision-making process? O a) Failure to develop enough options O b) Failure to correctly define the problem c) Failure to act on a decision O d) Failure to evaluate the decision
Answer:
failure to correctly define the problem
Step-by-step explanation:
He changes the menu without identify that the real problem was the service.
round 12.5478 to the nearest hundredths
Answer:
12.04
Step-by-step explanation:
Find the number in the hundredth place 4 and look one place to the right for the rounding digit 1 . Round up if this number is greater than or equal to 5 and round down if it is less than 5 .
Copy center charges $0.08 a page for machine fed copies and $0.20 for hand fed copies.If Logan's bill for 80 copies of his movie script is $13, how many copies of each type were made?
Answer:
machine fed copies = 25, hand fed copies = 55
Step-by-step explanation:
let machine fed = x, hand fed = y
0.08x+0.2y = 13 (1)
x+y = 80
x= 80-y (2)
sub (2) into (1)
0.08(80-y)+0.2y=13
6.4-0.08y+0.2y=13
0.12y=6.6
y = 55
sub y=55 into eqn 2
x = 80-55 = 25
Correct the formula
Please
Answer:
The addition should be divided by 4 and not 3 since there are 4 meals.
Step-by-step explanation:
