Answer:
Step-by-step explanation:
19 and 32
Answer:
the two numbers are 19 and 32
Step-by-step explanation:
let's call the numbers x and y.
write out the equations
x + y = 51
x - y = 13
simplify the second equation
x = 13 + y
substitute into the first equation and simplify
(13 + y) + y = 51
13 + 2y = 51
2y = 51 - 13
2y = 38
y = 19
substitute y for 19 in the second equation
x = 13 + y
x = 13 + 19
x = 32
A fish tank is initially filled with 400 liters of water containing 1 g/liter of dissolved oxygen. At noon, oxygenated water containing 10g/liter of oxygen flows in at a rate of 5 liters per minute and the well-mixed water is pumped out at a rate of 7 liters per minute.Let A(t) represent the amount of dissolved oxygen in the tank at time t. a) Write the differential equation that represents the problem.b) Solve the differential equation. c) At 1 p.m., what is the amount of dissolve oxygen in the fish tank
Answer:
a. [tex]dA(t)/dt = 50 - \frac{7A(t)}{400} where A(0) = 400[/tex]
b. [tex]A(t) = \frac{20000}{7} + \frac{17200}{7}e^{-7t/400}[/tex]
c. 3.717 kg
Step-by-step explanation:
a) Write the differential equation that represents the problem.
Let A(t) be the amount of dissolved oxygen in the tank at any time, t.
The net flow rate dA(t)/dt = mass flow in - mass flow out
Since 10 g/l of oxygen flows in at a rate of 5 l/min, the mass flow in is 10 g/l × 5 l/min = 50 g/min
Since A(t) is the amount of oxygen present in the tank at time, t, and the volume of the tank is 400 liters. The concentration of oxygen in the tank is thus A(t)/400 g/l.
Also, water is being pumped out at a rate of 7 l/min. So, the mass flow out is thus concentration × flow rate out = A(t)/400 g/l × 7 l/min = 7A(t)/400 g/min
So, dA(t)/dt = mass flow in - mass flow out
dA(t)/dt = 50 - 7A(t)/400 with A(0) = 400 l × 1 g/l = 400 g since the tank initially contains 1 g/l of dissolved oxygen and has a volume of 400 l
So, the differential equation is
dA(t)/dt = 50 - 7A(t)/400 where A(0) = 400 g
[tex]dA(t)/dt = 50 - \frac{7A(t)}{400} where A(0) = 400[/tex]
b) Solve the differential equation
To solve the equation, we use separation of variables, so
dA(t)/dt = 50 - 7A(t)/400 where A(0) = 400 g
dA(t)/(50 - 7A(t)/400) = dt
Integrating both sides, we have
∫dA(t)/(50 - 7A(t)/400) = ∫dt
-7/400 ÷ -7/400∫dA(t)/(50 - 7A(t)/400) = ∫dt
1/ (-7/400)∫-7/400dA(t)/(50 - 7A(t)/400) = ∫dt
(-400/7)㏑(50 - 7A(t)/400) = t + C
㏑(50 - 7A(t)/400) = -7t/400 + (-7/400)C
㏑(50 - 7A(t)/400) = -7t/400 + C' (C' = (-7/400)C)
taking exponents of both sides, we have
50 - 7A(t)/400 = exp[(-7t/400) + C']
50 - 7A(t)/400 = exp(-7t/400)expC'
[tex]50 - \frac{7A(t)}{400} = e^{-7t/400}e^{C'} \\50 - \frac{7A(t)}{400} = Ae^{-7t/400} A = e^{C'}\\ \frac{7A(t)}{400} = 50 - Ae^{-7t/400} \\A(t) = \frac{400}{7} X 50 - \frac{400}{7} Ae^{-7t/400} \\A(t) = \frac{20000}{7} - \frac{400}{7} Ae^{-7t/400}[/tex]
when t = 0 , A(0) = 400. So,
[tex]A(t) = \frac{20000}{7} - \frac{400}{7} Ae^{-7t/400} \\A(0) = \frac{20000}{7} - \frac{400}{7} Ae^{-7(0)/400}\\A(0) = \frac{20000}{7} - \frac{400}{7} Ae^{0/400}\\A(0) = \frac{20000}{7} - \frac{400}{7} Ae^{0}\\A(0) = \frac{20000}{7} - \frac{400}{7} A\\400 = \frac{20000}{7} - \frac{400}{7} A\\\frac{400}{7} A = 400 - \frac{20000}{7}\\\frac{400}{7} A = \frac{2800}{7} - \frac{20000}{7}\\\frac{400}{7} A = -\frac{17200}{7}\\\\A = -\frac{17200}{7} X \frac{7}{400} \\A = -43[/tex]
So,
[tex]A(t) = \frac{20000}{7} - \frac{400}{7} X -43e^{-7t/400} \\A(t) = \frac{20000}{7} + \frac{17200}{7}e^{-7t/400}[/tex]
c) At 1 p.m., what is the amount of dissolve oxygen in the fish tank.
At 1 p.m, t = 60 min
So, the amount of dissolved oxygen in the fish tank is A(60)
So,
[tex]A(t) = \frac{20000}{7} + \frac{17200}{7}e^{-7t/400}\\A(60) = \frac{20000}{7} + \frac{17200}{7}e^{-7X60/400}\\A(60) = \frac{20000}{7} + \frac{17200}{7}e^{-420/400}\\A(60) = \frac{20000}{7} + \frac{17200}{7}e^{-1.05}\\A(60) = \frac{20000}{7} + \frac{17200}{7} X 0.3499\\A(60) = \frac{20000}{7} + \frac{6018.93}{7} \\A(60) = \frac{26018.93}{7} \\A(60) = 3716.99 g[/tex]
A(60) ≅ 3717 g
A(60) ≅ 3.717 kg
I need to find the x of the triangle.
Please help me please!
Answer:
D) cannot factor
Step-by-step explanation:
D) cannot factor
D: cannot factor
it’s not factorable
8x+5x^3-5 write polynomial in standard form, Then name the polynomial based on the degree and number of terms
Answer:
wag na baka imyday mo pa
Step-by-step explanation:
hahahahahahahahahahahahahahahahahaahhaahahahahahhahahahahahahahahahahahahahahahahahahahahahahahahhahahahah ahahahahahahaha ahahahahahahaha ahahahahahahaha hahahahahah ahahahahahahaha
Select all ratios equivalent to 4:3.
Answer:
8:6 and 16:12
Step-by-step explanation:
In ΔRST, the measure of ∠T=90°, the measure of ∠S=16°, and ST = 2.9 feet. Find the length of TR to the nearest tenth of a foot.
Answer:
0.8
Step-by-step explanation:
-4x-2y=-12
4x+8y=-24
solve it by elimation
Answer:
(x, y) = (6, -6)
Step-by-step explanation:
Two parallel lines are cut by a transversal as shown below.
Suppose m 2 8 = 132º. Find m Z1 and m 2 3.
2.
4
3
5
6
8
8
7
Answer:
∠1 = ∠3 = 48
Step-by-step explanation:
∠8 = 132
∠4 = ∠8 {Corresponding angles}
∠4 = 132
∠1 +∠4 = 180 {Linear pair}
∠1 + 132 = 180
∠1 = 180 - 132
∠1 = 48
∠3 = ∠1 {Vertically opposite angles}
∠3 = 48
n x 5 = I'm very Smart *wink wink* I could just search it up I'm not gonna though okay
Answer:
5n
Step-by-step explanation:
find the sequence, i need help please
I am not usre what the answer could be
Answer:
[tex]x \le 5[/tex]
Step-by-step explanation:
Given
Shape: Cube
Dimensions: x, 3x and 2x
[tex]Volume < 900[/tex]
Required
Show that [tex]x \le 5[/tex]
First, calculate the volume
[tex]Volume = x * 3x * 2x[/tex]
[tex]Volume = 6x^3[/tex]
[tex]Volume < 900[/tex] becomes
[tex]6x^3 < 900[/tex]
Divide both sides by 9
[tex]x^3 < 150[/tex]
For [tex]x^3 < 150[/tex], the value of x as to be: 1, 2, 3, 4 or 5
Hence:
[tex]x \le 5[/tex]
Elmer is purchasing 2 4/5 pounds of candy that cost $1.85 per pound.
If he pays with $10, how much will he get in change? HELP I WILL MARK BRAINIEST
Answer:
hi
Step-by-step explanation:
Daniel bought 1 pound of jelly beans and 2 pounds of chocolates for $2.00. ... for $1.50. How much would he have to pay on his next trip to the candy store if he bought 1 pound of each of the 4 kinds ... How many are there? Assign ... Multiply each equation by a factor, so that all equations will have the same total price: 3(1j +.
Answer 1 and 2 please.
Answer:
Give me the questions and I'll edit my answer
Step-by-step explanation:
Answer:
what the question then I'll edit answer ;-;
Step-by-step explanation:
Which of the following properties is always true for a parallelogram?
A. Diagonals bisect each other
B. Diagonals are perpendicular
C. Diagonals are congruent
D. Diagonals bisect opposite angles
Answer:
c. is always true
Step-by-step explanation:
Which expression is equivalent to (xy^-6)^2 for all values of x and y where the expression is defined?
A. xy^-36
B. xy^ 36
C. x^2y^ -12
D. x^2y^ 12
Answer:
C.
First, you square the x because it is inside the parentheses. Then, you multiply the -6 by 2, to get your exponent of -12 for the y.
Answer:
[tex] \huge \boxed{ \boxed{ \mathbb{C)} {x}^{2} {y}^{ - 12} }}[/tex]
Step-by-step explanation:
to understand thisyou need to know about:law of exponentPEMDAStips and formulas:[tex] \sf( {x}^{m} {)}^{n} < = > {x}^{mn} [/tex][tex] \sf x < = > {x}^{1} [/tex]let's solve:[tex] step - 1 : define[/tex]
[tex] {(xy}^{ - 6} ) ^{2} [/tex]
[tex] \sf \: use \: 1st \: and \: 2nd \: formula : \\ ( {x}^{1 \times 2} {y}^{ - 6 \times 2} )[/tex][tex] \sf simplify : \\ {x}^{2} {y}^{ - 12} [/tex]Find the missing angle
Answer:
x=21
Step-by-step explanation:
69+90= 159
180-159=21
In one of ADNOC's onshore stations in the United Arab Emirates, oil is extracted and stored in large cylindrical tanks. If one of the tanks is 30
meters deep and 20 meters in diameter, find the Volume of the tank, use 3.14 for
(show your work)
Answer: 9420meters³
Step-by-step explanation:
The formula to calculate the volume of the cylindrical tank will be:
= πr²h.
where,
π = 3.14
r = radius = diameter/2 = 20/2 = 10
h = height = 30
Volume = πr²h
= 3.14 × 10² × 30
= 3.14 × 100 × 30
= 9420meters³
how to write 1/4z-1/3-1/7z^2 in az^2+bz
Answer:
huh?nani?
ksjn
lsjsmskkks
WILL MARK BRAINLEST PLS HELP ME Find the area of the circle. Round to the nearest tenth. Use 3.14 for it.
32 m
The area of the circle is about
m2.
Answer:
[tex]804.3m^2[/tex]
[tex]\pi *16^2=804.24772[/tex]
Help me pls! this is due tonite . I'm doing a ged practice test and I just have a few questions I haven't answered
When 36x⁴ + 12x⁸ is divided by 12x⁴ the result is:
A) 3+12x8
B)3+x⁴
C)3x+x²
Answer:
Step-by-step explanation:
36x⁴ /12x⁴ + 12x⁸ / 12x⁴
3x+x²
Mary has two sisters. Her younger sister is 5 years younger Her older
sister is twice her age. Their ages add up to 47. How dd is Mary and each
of her sisters?
If the complex number x = 3 + bi and |x|2 = 13, which is a possible value of b?
2
4
9
10
Answer:
A: 2
Step-by-step explanation:
EDGE 2021
Considering that the magnitude of the complex number x is of 13, a possible value of b is of 2.
What is a complex number?A complex number is modeled by:
z = a + bi.
In which:
a is the real part.b is the imaginary part.In this problem, the number is:
x = 3 + bi.
It's magnitude is given by:
[tex]|x| = \sqrt{3^2 + b^2}[/tex]
Then:
[tex]\sqrt{3^2 + b^2} = \sqrt{13}[/tex]
[tex]3^2 + b^2 = 13[/tex]
[tex]b = \pm \sqrt{4}[/tex]
[tex]b = \pm 2[/tex]
A possible value of b is of 2.
More can be learned about complex numbers at https://brainly.com/question/25572463
#SPJ2
A farmer sells 8.9 kilograms of apples and pears at the farmer's market. 3/5 of this weight is apples, and the rest is pears. How many kilograms of pears did she sell at the farmer's market?
Write this number in scientific notation 56,023,987
Then solve this what I get?
A -1
B 2
C 1
D -2
Answer:
-1
Step-by-step explanation:
Which of the following is a characteristic of all parallelograms?
Answer:
The opposite sides are always parallel.
7. If it takes 2 gardeners 6 hours to landscape a garden, how long would
it take 3 gardeners?
Enter your answer
Question 7 is an example of...
Direct proportion
Inverse proportion
Answer:
it will take 12 hours
Step-by-step expl
I am in need of help please.
Answer:
80 ft
Step-by-step explanation:
i dont really know if this is the right answer plz tell me if im wrong
Distribute. 8(x+30)+5
Answer:
8x + 245
Step-by-step explanation:
8(x + 30) + 5
8x + 240 +5
8x + 245
good luck, i hope this helps :)
the Rangers played 40 games. They won 18 more games then they lost. How many games did they win?
9514 1404 393
Answer:
29
Step-by-step explanation:
Let w represent the number of wins. Then the number of losses is w-18. The total number of games played is ...
wins + losses = 40
w + (w-18) = 40
2w = 58
w = 29
The Rangers won 29 games.