tank contains 250 liters of fluid in which 20 grams of salt is dissolved. Pure water is then pumped into the tank at a rate of 5 L/min; the well-mixed solution is pumped out at the same rate. Find the number A(t) of grams of salt in the tank at time t.
Solution :
Given data :
[tex]c_{in}[/tex] = 1 g/L
[tex]r_{in}[/tex] = 5 L/min
[tex]r_{out}[/tex] = 5 L/min
[tex]$v_0$[/tex] = 250 L
[tex]A_0[/tex] = 20 g
∴ [tex]r_{net} = r_{in}- r_{out}[/tex]
= 5 - 5
= 0
[tex]c_{out} = \frac{A}{250} \ g/L[/tex]
Now, [tex]\frac{dA}{dt}=(r_{in} \times c_{in}) - (r_{out} \times c_{out})[/tex]
[tex]$\frac{dA}{dt} = 5-5\left(\frac{A}{250}\right)$[/tex]
[tex]\frac{dA}{dt}+5 \left(\frac{A}{250}\right) = 5[/tex]
[tex]\frac{dA}{dt}+5 \left(\frac{A}{250}\right) = 5 \text{ with} \ A_0 = 20[/tex]
Integrating factor = exp(5 t/250)
Therefore,
[tex]A \times \exp (5t \ /250) = \text{integral of}\ 5 \times \exp (5t / 250) + C[/tex]
Put [tex]A_0=250+C[/tex]
C = -230
[tex]A \times \exp(5t/250) = 250 \exp(5t/250) + (-230)[/tex]
[tex]A(t) = 250-230 \exp(-5t/250)[/tex]
[tex]A(t) = 250-230e^{\left(\frac{-t}{50}\right)} \ g[/tex]
Andrew walks 2000 feet from his house to his office. What distance does he cover?
A. 18,000 in.
B. 24,000 in.
C. 25,000 in.
D. 30,000 in.
What is the y-intercept of function f?
A. 1
B. -1
C. -2
D. 5
Answer:
1
Step-by-step explanation:
The y intercept is when x =0
We need to use the second equation
-x+1 since -2 < 0 <3
0+1
The y intercept is 1
I’m having a hard time anyone knows??
Answer:
65
Step-by-step explanation:
See image below:)
Which expression is equivalent to 1/2x + 8
Answer:
1/2( x+16)
Step-by-step explanation:
1/2x + 8
Factor out 1/2
1/2*x + 1/2 *16
1/2( x+16)
What is the median of 6, 7, 3, 15, 4, 4.
Answer:
5
Step-by-step explanation:
The median is the middle when the numbers are lined up from smallest to largest
3,4,4,6,7,15
There are 6 number so the middle is the between the 3rd and 4th number
3,4,4, 6,7,15
Take the 3rd and 4th numbers and average
(4+6)/2 = 10/2 = 5
Answer:
median = 5
Step-by-step explanation:
Arrange the data in ascending order :
3 , 4 , 4 , 6 , 7 , 15
Choose the middle number.
Here there are even number of data. Take the average of the middle
numbers .
4 and 6 are the middle number. average of 4 and 6 = ( 4 + 6 ) /2 = 5
Therefore , median = 5
Write the equation of the line passing through the point (−3,−4) that is perpendicular to y=8/3x+5.
Answer:
y = -3/8x -41/8
Step-by-step explanation:
Perpendicular lines intersect at 90° and their slopes are opposite reciprocals.
Therefore the slope changes from 8/3 to -3/8.
Now we must solve for the new y-intercept (b) by plugging in the given coordinate (-3,-4).
The result is b = -41/8 so our new equation is:
y = -3/8x -41/8
PLEASE HELP ASAP WILL GIVE BRAINLEIST FOR AN ACTUAL ANSWER
Answer:
<V = 40
Step-by-step explanation:
The exterior angle is equal to the sum of the opposite interior angles
20x = 60+7x+5
Combine like terms
20x = 7x+65
Subtract 7x from each side
20x -7x = 7x+65-7x
13x = 65
Divide each side by 13
13x/13 = 65/13
x = 5
<v = 7x+5 = 7*5+5 = 35+5 = 40
answer:
it's U = 60°
V = 50°
T = 70°
PLEASE HELP ME !!!! WILL GIVE BRAINLIEST TO WHOEVER ANSWERS CORRECTLY
Answer:
(8x + 1)° + ( 4x+11)° = 180° (linear pair )
8x +1 + 4x +11 = 180
8x + 4x + 1 + 11 = 180
12x + 12 = 180
12x = 180 - 12
12x = 168
x= 168/12
x = 14
A certain country has 586.08 million acres of forest. Every year, the country loses 7.92 million acres of forest mainly due to deforestation for farming purposes. If this situation continues at this pace, how many years later will the country have only 237.6 million acres of forest left? (Use an equation to solve this problem.)
Answer:
At this pace the country will have only 237.6 million acres of forest left in 44 years.
Step-by-step explanation:
Given that a certain country has 586.08 million acres of forest, and every year, the country loses 7.92 million acres of forest mainly due to deforestation for farming purposes, to determine, if this situation continues at this pace, how many years later will the country have only 237.6 million acres of forest left, the following calculation must be performed:
Current amount - (amount lost per year x number of years) = 237.6
586.08 - (7.92 x X) = 237.6
586.08 - 7.92X = 237.6
-7.92X = 237.6 - 586.08
-7.92X = -348.48
X = -348.48 / -7.92
X = 44
Therefore, at this pace the country will have only 237.6 million acres of forest left in 44 years.
Shana has three pets, a dog, a cat and a bird. One of them is named Sammy. Noodles is younger than both the bird and the dog. Fluffy is green. Which pet has the name Sammy?
Answer:
The dog has the name Sammy.
Step-by-step explanation:
A cat and dog cannot be green, therefore the bird is Fluffly.
Noodles must be the cat since it's younger than the bird and the dog.
The only one that doesn't have an explanation is the dog, therefore the dog must be named Sammy.
Help me please I NEED to pass this
OPTION C is the correct answer.
Hope it helps you.
Help pleaseeeee will give brainliest
Answer:
q.12
angle ACB=180-123
therefore ACB=57
again 5x-15+7x+6+57=180
or,12x+48=180
or,x=132/12
or x=11
The diameter of the stem of a wheat plant is an important trait because of its relationship to breakage of the stem. An agronomist measured stem diameter in eight plants of a particular type of wheat. The mean of these data is 2.275 and the standard deviation is 0.238. Construct a 80% confidence interval for the population mean.
Answer:
7.79771≤x≤8.20229
Step-by-step explanation:
Given the following
sample size n = 8
standard deviation s = 0.238
Sample mean = 2.275
z-score at 980% = 1.282
Confidence Interval = x ± z×s/√n
Confidence Interval = 8 ± 1.282×0.238/1.5083)
Confidence Interval = 8 ± (1.282×0.15779)
Confidence Interval = 8 ±0.20229
CI = {8-0.20229, 8+0.20229}
CI = {7.79771, 8.20229}
Hence the required confidence interval is 7.79771≤x≤8.20229
Mention 3 places
where you can get
pre-approved for a
car loan
Answer:
Auto Credit Express, Carvana, Capital one auto loan
A construction crew is lengthening a road that originally measured 47 miles. The crew is adding one mile to the road each day. Let L be the length (in miles) after D days of construction. Write an equation relating L to D. Then use this equation to find the length of the road after 31 days.
Answer:
78 miles
Step-by-step explanation:
Given that:
Original length, L = 47 miles
Additional length (miles) added per day, = 1 mile
Representing as an equation :
L(D) = original length + additional length per day * number of days
Let, D = number of days
L(D) = 47 + D
Length after 31 days :
L(31) = 47 + 31
= 78 miles
The sum of two numbers in 106 and the greater exceeds the lesser in 8. Find the numbers.
Step-by-step explanation:
51 and 51
maybe
hope it help u(8,9); x+3y=2 in y=mx+b form
Answer:
use photo math. it will help
What are the coordinates of Point P?
Answer:
(-1.5, 0.5)
Step-by-step explanation:
x = -1.5
y = 0.5
(-1.5, 0.5)
Select the correct answer.
What is the factored form of this expression?
-12x+36
ОА.(x - 12)(x-3)
O B. (x - 6)^2
OC. (x + 6)^2
OD. (x-6)(x+6)
The answer is B
the method use to solved this is called foil
Easy question please help
Answer:
[tex]y = 3x - 2[/tex]
Step-by-step explanation:
Required
The equation of the above linear function
From the table, we have:
[tex](x_1,y_1) = (1,1)[/tex]
[tex](x_2,y_2) = (2,4)[/tex]
Calculate slope (m)
[tex]m = \frac{y_2 -y_1}{x_2 -x_1}[/tex]
[tex]m = \frac{4 -1}{2 -1}[/tex]
[tex]m = \frac{3}{1}[/tex]
[tex]m =3[/tex]
The equation is:
[tex]y = m(x - x_1) + y_1[/tex]
So, we have:
[tex]y = 3(x - 1) + 1[/tex]
[tex]y = 3x - 3 + 1[/tex]
[tex]y = 3x - 2[/tex]
An eagle flies towards south luzon at 90 meters for 5 seconds . What is the speed and velocity of the eagle
Answer:
the speed in 18mph
Step-by-step explanation:
A random sample of 30 patties that were inspected over the course of the last week revealed that the average weight was 95.0 grams. The standard deviation was 0.25 grams. What percentage of the deliveries is likely to be outside the specification limits (outside the interval of [94.5, 95.5])
Answer:
4.56% of the deliveries are likely to be outside the specification limits.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
The average weight was 95.0 grams. The standard deviation was 0.25 grams.
This means that [tex]\mu = 95, \sigma = 0.25[/tex]
What percentage of the deliveries is likely to be outside the specification limits (outside the interval of [94.5, 95.5])?
Less than 94.5, or more than 95.5. Since the normal distribution is symmetric, these probabilities are the same, so we can find one of them and multiply by two.
The probability that it is less than 94.5 is the p-value of Z when X = 94.5. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{94.5 - 95}{0.25}[/tex]
[tex]Z = -2[/tex]
[tex]Z = -2[/tex] has a p-value of 0.0228
2*0.0228 = 0.0456
0.0456*100% = 4.56%
4.56% of the deliveries are likely to be outside the specification limits.
Will choose brainliest! Please help! (This is Khan Academy)
Answer:
Option B. A = (5/6)^-⅛
Step-by-step explanation:
From the question given above, we obtained:
(5/6)ˣ = A¯⁸ˣ
We can obtain the value of A as follow:
(5/6)ˣ = A¯⁸ˣ
Cancel x from both side
5/6 = A¯⁸
Recall:
M¯ⁿ = 1/Mⁿ
A¯⁸ = 1/A⁸
Thus,
5/6 = 1/A⁸
Cross multiply
5 × A⁸ = 6
Divide both side by 5
A⁸ = 6/5
Take the 8th root of both sides
A = ⁸√(6/5)
Recall
ⁿ√M = M^1/n
Thus,
⁸√(6/5) = (6/5)^⅛
Therefore,
A = (6/5)^⅛
Recall:
(A/B)ⁿ = (B/A)¯ⁿ
(6/5)^⅛ = (5/6)^-⅛
Therefore,
A = (5/6)^-⅛
A department store manager noted that the sales of furniture contributed 20% of the store's profits in the year 2015 and 29% in the year 2016.
Of the following choices, which two statements about furniture sales are true?
a.) There was a 45% increase in furniture sales.
b.) Furniture sales rose by 45 percentage points.
c.) There was a 31% increase in furniture sales.
d.) There was a 9% increase in furniture sales.
e.) Furniture sales rose by 31 percentage points.
f.) Furniture sales rose by 9 percentage points.
Answer:
There was a 45% increase in furniture sales.
Furniture sales rose by 9 percentage points.
Step-by-step explanation:
absolute difference = new - old
29-20= 9 percentage points
absolute difference / initial value = 9/20 = .45 * 100 = 45%
Two statements which are true about furniture sales are [tex](a)[/tex] There was a [tex]45\%[/tex] increase in furniture sales and [tex](f)[/tex] Furniture sales rose by [tex]9[/tex] percentage points.
What is percentage ?Percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%".
Percentage [tex]=\frac{Obtained\ number}{Total\ number}\ * 100[/tex]
We have,
Sales of furniture in [tex]2015=20\%[/tex]
Sales of furniture in [tex]2016=29\%[/tex],
So,
Change in Percentage [tex]=29-20=9\%[/tex]
i.e.
Sales rise by [tex]9\%[/tex] points,
And,
Increase in Percentage [tex]=\frac{9}{20}\ *100=45\%[/tex]
Hence, we can say that Two statements which are true about furniture sales are [tex](a)[/tex] There was a [tex]45\%[/tex] increase in furniture sales and [tex](f)[/tex] Furniture sales rose by [tex]9[/tex] percentage points.
To know more about Percentage click here
https://brainly.com/question/24159063
#SPJ3
{2x + y = -1}
{3x- 5y + -21}
Answer:
(-2, 3).
Step-by-step explanation:
2x + y = -1
3x- 5y = -21
Multiply the first equation by 5:
10x + 5y = -5 Adding this to the second equation:
13x = -26
x = -2.
Substituting this into equation 1:
2(-2) + y = -1
y = -1 + 4 = 3.
Checking this result in the second equation:
3(-2) - 5(3)
= -5 - 15 = -21
- Checks OK.
On a coordinate plane, triangle B C D has points (negative 4, 1), (negative 2, 1), (negative 4, 3). Triangle B prime C prime D prime has points (negative 1, negative 4), (negative 1, negative 2), (negative 3, negative 4). Triangle BCD is rotated counterclockwise to form triangle B’C’D’. What is the angle of rotation? 45° 90° 180° 360°
9514 1404 393
Answer:
90° CCW
Step-by-step explanation:
The transformation from B to B' is ...
B(-4, 1) ⇒ B'(-1, -4)
(x, y) ⇒ (-y, x) . . . . . matches the transformation for 90° CCW
Answer:
90 degrees
Step-by-step explanation:
x over 3 add 5 = 5
Pls help someone
Answer:
x=0
Step-by-step explanation:
0/3 = 0
0+5=5
Which is the better value for money 250g of coffee R12,35 or 450g of the same coffee at R21,95
Answer:
450g coffee or 21.95$ coffee
Step-by-step explanation:
again, divide whichever pair you want to and you still have the same answer whether it is less or more: 450/250 is math would be 9/5 and 21.95/12.35 is 1.77732793522. so if we find the true value of 9/5, which is 1.8, and since it is more that the original price that means the more coffe you get, the cheaper it gets (basically all of life is like this), so the 450 g coffee is worth alot less than and is bigger than the 250 g coffee
A man bought a car for $8200 and sold it for 80% of the price two years later. How much did he lose?
Answer:
I don't know for sure, but I'm pretty sure its 1,640.
Step-by-step explanation:
80% of 8,200 is 6560, and then do 8,200- 6,560, you get 1,640.
[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]
According to question, The price at which it was sold is equal to :
[tex]80 \% \: \: of \: \: 8200[/tex][tex] \dfrac{80}{100} \times 8200[/tex][tex]80 \times 82[/tex][tex]6560[/tex]The car was sold at $ 6560
Now, loss is equal to :
[tex]8200 - 6560[/tex][tex] \$ \: 1640[/tex]