Answer:
B) 67°C.
Step-by-step explanation:
Newton's Law of Cooling is given by:
[tex]\displaystyle \frac{dT}{dt}=k(T-A)[/tex]
Where T is the temperature of the coffee, A is the room temperature, and k is a positive constant.
We are given that the coffee cools from 100°C to 90°C in one minute at a room temperature A of 25°C.
And we want to find the temperature of the coffee after four minutes.
First, solve the differential equation. Multiply both sides by dt and divide both sides by (T - A). Hence:
[tex]\displaystyle \frac{dT}{T-A}=k\, dt[/tex]
Take the integral of both sides:
[tex]\displaystyle \int \frac{dT}{T-A}=\int k\, dt[/tex]
Integrate:
[tex]\displaystyle \ln\left|T-A\right| = kt+C[/tex]
Raise both sides to e:
[tex]|T-A|=e^{kt+C}=Ce^{kt}[/tex]
The temperature of the coffee T will always be greater than or equal to the room temperature A. Thus, we can remove the absolute value:
[tex]\displaystyle T=Ce^{kt}+A[/tex]
We are given that A = 25. Hence:
[tex]\displaystyle T=Ce^{kt}+25[/tex]
Since the coffee cools from 100°C to 90°C, the initial temperature of the coffee was 100°C. Thus, when t = 0,T = 100:
[tex]100=Ce^{k(0)}+25\Rightarrow C=75[/tex]
Hence:
[tex]T=75e^{kt}+25[/tex]
We are given that the coffee cools from 100°C to 90°C after one minute at a room temperature of 25°C.
So, T = 90 given that t = 1. Substitute:
[tex]90=75e^{k(1)}+25[/tex]
Solve for k:
[tex]\displaystyle e^k=\frac{13}{15}\Rightarrow k=\ln\left(\frac{13}{15}\right)[/tex]
Therefore:
[tex]\displaystyle T=75e^{\ln({}^{13}\! /\!{}_{15})t}+25[/tex]
Then after four minutes, the temperature of the coffee will be:
[tex]\displaystyle \begin{aligned} \displaystyle T&=75e^{\ln({}^{13}\! /\!{}_{15})(4)}+25\\\\&\approx 67^\circ\text{C}\end{aligned}[/tex]
Hence, our answer is B.
Which of the following is the logical conclusion to the conditional statements below? a arrow b mb arrow c
Answer:
B
Step-by-step explanation:
From what we have here;
if a implies b and b implies c
It simply means that we have a implying c
the correct representation here is given in the second option
And thus, we have it that;
a => c
G(x)=√8x
What is the domain of g?
Answer:
answer is b
Step-by-step explanation:
got it right on khan
The domain of the function g(x) = √(8x) is all real numbers greater than or equal to 0, which can be expressed as [0, +∞).
option B is correct.
Here, we have,
The domain of a function refers to the set of all possible input values (x-values) for which the function is defined.
For the given function g(x) = √(8x), the function is defined as long as the expression inside the square root (√) is non-negative.
In this case, the expression inside the square root is 8x.
To ensure that it is non-negative, we need 8x ≥ 0.
Solving the inequality, we find:
8x ≥ 0
x ≥ 0/8
x ≥ 0.
Therefore, the domain of the function g(x) = √(8x) is all real numbers greater than or equal to 0, which can be expressed as [0, +∞).
To learn more on function click:
brainly.com/question/21145944
#SPJ4
Distribute an amount of Rs. 200 between Raheem and Usman such that Raheem
gets RS 50 more than twice as much as Usman gets .
Answer:
50 and 150
Step-by-step explanation:
Raheem- (2x+50)
Usman- x
(2x+50)+x=200
3x+50=200
3x=150
x=50
plug in the numbers
Joshua is 1.45 meters tall. At 2 p.m., he measures the length of a tree's shadow to be 31.65 meters. He stands 26.2 meters away from the tree, so that the tip of his shadow meets the tip of the tree's shadow. Find the height of the tree to the nearest hundredth of a meter .
Answer:
8.42
Step-by-step explanation:
* means multiply
31.65/5.45 = x/1.45
5.45x = 31.65 * 1.45
5.45x = 45.8925
x = 45.8925/5.45
x = 8.42064220183
solve the simultaneous equation: y=2x²+3x-31 y= x= 21-2x
Answer:
1. x =(3-√257)/4=-3.258
2. x =(3+√257)/4= 4.758
Step-by-step explanation:
irst add
x
to both sides of the second equation to get:
y = x + 3
Then substitute this expression for y into the first equation to get:
29 = x 2 + ( x + 3 ) 2 = 2 x 2 + 6 x + 9
Subtract 29 from both ends to get:
0 = 2 x 2 + 6 x − 20
Divide both sides by 2 to get:
0 = x 2 + 3 x− 10 = ( x+ 5 ) ( x − 2 )
So x = 2 or x = − 5
If x = 2 then y = x + 3 = 5 .
If x = − 5 then y=x + 3 = − 2
So the two solutions
( x, y ) are ( 2 , 5 ) and ( − 5 , − 2 )
Which ordered pair is a solution of 2x+4y=6x-y
Answer:
5y=4x
Step-by-step explanation:
Which is the largest three-digit number of the form 9k + 1, where k is any positive integer?
Answer:
991
Step-by-step explanation:
We are looking for a number that is one more than a multiple of 9(denoted by the 9k) and is a three digit number. We can start by looking for 3-digit number divisible by 9 which are close to 1,000, since that is the next number larger than the largest three-digit number. We can tell that 999 is divisible by 9 because when divided it does not leave a remainder(you can also figure this out with divisibility tricks). We add one to get 1,000. This is not a three-digit number, so we need to look for a smaller multiple of 9. Subtracting 9 from 999, we get the next largest multiple of 9. We can add 1, and this time, the number, 991, is a three digit number, and the largest that can be in the form 9k + 1.
Does anyone know the answer to this question?
Answer:
Step-by-step explanation:
Third graph because when x is greater than two the lines slants up
Kylie explained that (negative 4 x + 9) squared will result in a difference of squares because (negative 4 x + 9) squared = (negative 4 x) squared + (9) squared = 16 x squared + 81. Which statement best describes Kylie’s explanation?
Kylie is correct.
Kylie correctly understood that it is a difference of squares, but she did not determine the product correctly.
Kylie did not understand that this is a perfect square trinomial, and she did not determine the product correctly.
Kylie determined the product correctly, but she did not understand that this is a perfect square trinomial.
Given:
The given expression is:
[tex](-4x+9)^2[/tex]
According to Kylie,
[tex](-4x+9)^2=(-4x)^2+(9)^2[/tex]
[tex](-4x+9)^2=16x^2+81[/tex]
To find:
The correct statement for Kylie's explanation.
Solution:
We have,
[tex](-4x+9)^2[/tex]
According to the perfect square trinomial [tex](a+b)^2=a^2+2ab+b^2[/tex].
[tex](-4x+9)^2=(-4x)^2+2(-4x)(9)+(9)^2[/tex]
[tex](-4x+9)^2=16x^2-72x+81[/tex]
Kylie did not understand that this is a perfect square trinomial, and she did not determine the product correctly.
Therefore, the correct option is C.
Answer:C, Kylie did not understand that this is a perfect square trinomial, and she did not determine the product correctly.
Step-by-step explanation:
Please help! will mark right answer with Brianly
Answer:
a. [tex]\frac{4\pi }{3}[/tex]
b. 240
Step-by-step explanation:
all you have to do to find a coterminal angle is to add or subtract 360 or [tex]2\pi[/tex] from the angle, so:
a. [tex]\frac{10\pi }{3} -2\pi =\frac{4\pi }{3}[/tex]
b. -120 + 360 = 240
Find the TWO integers whos product is -12 and whose sum is 1
m
Answer:
[tex] \rm Numbers = 4 \ and \ -3.[/tex]
Step-by-step explanation:
Given :-
The sum of two numbers is 1 .
The product of the nos . is 12 .
And we need to find out the numbers. So let us take ,
First number be x
Second number be 1-x .
According to first condition :-
[tex]\rm\implies 1st \ number * 2nd \ number= -12\\\\\rm\implies x(1-x)=-12\\\\\rm\implies x - x^2=-12\\\\\rm\implies x^2-x-12=0\\\\\rm\implies x^2-4x+3x-12=0\\\\\rm\implies x(x-4)+3(x-4)=0\\\\\rm\implies (x-4)(x+3)=0\\\\\rm\implies\boxed{\red{\rm x = 4 , -3 }}[/tex]
Hence the numbers are 4 and -3.
Answer:
-3,4 are the TWO integers whos product is -12 and whose sum is 1.
Step-by-step explanation:
-3×4=12
-3+4=1
Find each measure
Please help me
Answer:
11. 90
12. 90
13. 90
14. 90
15. 180
16. 135
17. 225
18. 270
Step-by-step explanation:
Answer:
BC=90
AC=90
AE=90
EB=90
ACB=180
AD=135
CBF=225
ADC=270
Step-by-step explanation:
for numbers 11-14 they're all linear pairs which means they're each 90 degrees
and as long as O is the center point, all the arcs are the same value as the degree.
for numbers 16-17 you can assume that line FO and DO bisects the right angles which makes them 45 degrees
and for 18, you just multiply 3 and 90 degrees
Can someone help with 3 and 9
Answer:
9= 512m/1000m
SIMPLIFY IT
Step-by-step explanation:
A body is projected from aa point such that the horizontal and vertical components of its velocity are [tex]640ms^-^1[/tex] and [tex]480 ms^-^1[/tex] respectively . (Take g = [tex]10ms^-^1[/tex] )
i. Calculate the greatest height attained above the point of projection
A.600m B.1215 m C.1521 m D. 11520m E. 20480m
D. 11520m
Answer:
Solution given:
initial velocity[u]=480m/s
g=10m/s²
maximum height=?
now
we have
maximum height=[tex]\frac{u²sin²\theta}{2g}[/tex]
where
[tex]\theta=90°[/tex]
=[tex]\frac{480²*sin90}{2*10}=11520m[/tex]
If 69 +69 +69 = 69 then what does 69 +69-69= plz help I need it
Answer:
69??
Step-by-step explanation:
.
Answer: It would still be 69.
Step-by-step explanation: When you add the both of the 69's together you would get 138 but when you subtract 69 you end up with 69 so therefore it's still 69.
7. The revenue for the school play is given by: R= -50t^2 + 300t , where “t” is the ticket price in dollars. The cost to produce the play is given by: C = 600-50t. Determine the ticket price that will allow the school play to break even. (Note: breaking even means that revenue = cost.) Sketch the graphs of both equations as seen on your calculator (indicate the window you used
in the space provided).
Answer:
R= -50t^2 + 300t
-50tt(t-6)
-50(t-12)
so lets say that they sold 10 dollar tickets
-5000(4)
so they would lose -20000 dollars
-50(-2)
and the play would cost 100 dollars
Hope This Helps!!!
What is 6 1/3 divied by 1/6
Answer:
38
Step-by-step explanation:
6⅓÷⅙
change 6⅓ to improper fraction
19/3÷1/6
keep the first fraction, change the division sign to multiplication and reciprocate/flip the second fraction
19/3× 6/1
the denominator 3 and numerator 6 will simplify/cancel each other
the new fraction is now: 19/1 × 2/1
there is no need to multiply the denominators because it will still be equal to 1 so we just need to multiply the numerators by each other
19×2=38 OR 38/1 (both answers are the same)
write a equation for y=|x| if the graph is translated right by 3 units and down by 1 unit
Answer:
y=|x -3| -1
Step-by-step explanation:
x + 2y when x = 1 and y = 4
Answer:
9
Step-by-step explanation:
x = 1
y = 4
x + 2y = 1 + 8 = 9
If my answer is incorrect, pls correct me!
If you like my answer and explanation, mark me as brainliest!
-Chetan K
Answer:
9
Step-by-step explanation:
x + 2y
subtitute:
1 + 2(4)
simplify:
1 + 8 = 9
This is the last question for the 12 point
9514 1404 393
Answer:
WR ≅ WX
Step-by-step explanation:
To use the SAS postulate, you need congruent sides bounding a congruent angle.
Here, side WP is one side of one of the vertical angles, ∠PWR, so you need the other side of that angle: WR. The corresponding side in triangle VWX is WX. That is, for SAS, you need WR ≅ WX.
Carol ran a 100 meter race in 13. 4 seconds. But, it was wrongly
measured as 14.1 seconds. What is the percent error involved in the
measurement?
Answer: Approximately 5.22%
========================================================
Work Shown:
A = true value = 13.4 seconds
B = measured value (erroneous value) = 14.1 seconds
C = percent error
C = [ (B-A)/A ] * 100%
C = [ (14.1-13.4)/(13.4) ] * 100%
C = 0.0522 * 100%
C = 5.22%
This value is approximate.
Name a pair of vectors that are orthogonal but not perpendicular.
Answer:
For two vectors to be orthogonal it means that their dot product must be equal to zero.
Usually dot product of perpendicular vectors is zero and thus all perpendicular vectors are orthogonal.
Solve the inequality. 2 + |t + 6| < 12
Answer:
[tex]2 + (t + 6) < 12[/tex]
[tex]2 + t + 6 < 12[/tex]
[tex]t + 8 < 12[/tex]
[tex]t < 12 - 8[/tex]
[tex]t < 8[/tex]
What Is the factored form of the polynomial
x^2-12x+27
Step-by-step explanation:
The Answer is (x-9) (x-3) Factor 12 and 27 out.
Answer:
[tex]x^{2} -12x+27=[/tex]
[tex](x-3)and\:(x-9)[/tex]
-----------------------
hope it helps...
have a great day!!
tengo estos problemas de algebra alguien que me atude porfavor !?
Answer:
I think 3 but I am not pretty sure man .
Bonjour,
x est un nombre d'ordinateurs: il est donc un naturel (x € N)
y is the pay cost : y=3*x ==> y€ 3N ⊂ N
Answer last reply : 4.
Help please
……………………..
Answer:
b ≈ 48.6°
Step-by-step explanation:
Using the sine ratio in the right triangle
sin b = [tex]\frac{opposite}{hypotenuse}[/tex] = [tex]\frac{9}{12}[/tex] , then
b = [tex]sin^{-1}[/tex] ([tex]\frac{9}{12}[/tex] ) ≈ 48.6° ( to 1 dec. place )
Find x and y
Help me please
Answer:
x = 70 y = 140
Step-by-step explanation:
Apologies if I get any names of vocabulary terms wrong, I never pay much attention to the names.
The central angle measure of an arc is the same as the arc's measure. In this case, y is the central angle and 140 is the arc's measure, so y = 140.
The inscribed angle measure of an arc is 1/2 the arc's measure. An inscribed angle lies on the circle. So 140/2 = 70 = x.
HURRY NEED ASAP TRYNA FINISH SUMMER SCHOOL LOL, I WILL MARK BRAINLIEST :)) PICTURE IS THERE FOR U
Answer:
B.
Step-by-step explanation:
Since the numbers in the root is all the same, lets say [tex]\sqrt{2}[/tex] is a variable.
7x[tex]\sqrt{2}[/tex] - 4[tex]\sqrt{2}[/tex] + x[tex]\sqrt{2}[/tex]
Group with like terms:
7x[tex]\sqrt{2}[/tex] + x[tex]\sqrt{2}[/tex] - 4[tex]\sqrt{2}[/tex]
Combine like terms:
8x[tex]\sqrt{2}[/tex] - 4[tex]\sqrt{2}[/tex]
There you have it! Since all the square roots are the same thing, we can treat them like variables.
the answer is B..................
Factor -1.8 out of 3.6b-9
=================================================
Explanation:
Consider something like 2b+6 factoring to 2(b+3). When we distribute that outer 2 back inside the parenthesis, we're multiplying that 2 by everything inside. Factoring goes in reverse of this and we divide each term of 2b+6 by the GCF 2.
The same thing applies to this current problem as well.
Divide each term by the -1.8 we want to factor out.
(3.6b)/(-1.8) = -2b(-9)/(-1.8) = 5The results -2b and 5 will go inside the parenthesis. That's how we end up with -1.8(-2b+5)
You can use distribution to verify this
-1.8(-2b+5)
-1.8*(-2b) - 1.8*(5)
3.6b - 9
IM TIMED HALP!!!
Relationship A and Relationship B show the change in the temperature for a pot of water on the stove. Relationship B has a greater rate than Relationship A.
This table represents Relationship A.
Time (min) 2 3 7 9
Temperature (°C) 61.3 64.9 79.3 86.5
What table could represent Relationship B?
Time (min) 2 3 7 9
Temperature (°C) 61.0 64.6 79.0 86.2
Time (min) 2 3 7 9
Temperature (°C) 60.6 64.3 79.1 86.5
Time (min) 2 3 7 9
Temperature (°C) 61.0 64.4 78.0 84.8
Time (min) 2 3 7 9
Temperature (°C) 61.8 65.3 79.3 86.3
Answer:
The table representing Relationship B is option 2
[tex]\begin{array}{ccc}Time \ (min)&&Temperature \ (^{\circ}C)\\2&&60.6\\3&&64.3\\7&&79.1\\9&&86.5\end{array}[/tex]
Step-by-step explanation:
The relationship shown by Relationship A and Relationship B = The change in the temperature for a pot of water om the stove
The rate of Relationship B > The rate of Relationship A
The table for relationship A is given as follows';
[tex]\begin{array}{ccc}Time \ (min)&&Temperature \ (^{\circ}C)\\2&&61.3\\3&&64.9\\7&&79.3\\9&&86.5\end{array}[/tex]
The time in minutes are the x-values, while the temperature in °C Ere the y-values
The rate for Relationship A, [tex]m_A[/tex] = (86.5 - 61.3)/(9 - 2) = 3.6
Therefore, the rate for Relationship B > 3.6
By checking each option, we note that in option 2, the maximum value for the y-value is the same as for Relationship A, which is 86.5°C, while the minimum value for the time, t, is lesser than that for Relationship A, (60.6 minutes < 61.3 minutes) therefore, we get;
The rate for option 2 = (86.5 - 60.6)/(9 - 2) = 3.7
Therefore, the table that represents the Relationship B is the table for option 2
[tex]\begin{array}{ccc}Time \ (min)&&Temperature \ (^{\circ}C)\\2&&60.6\\3&&64.3\\7&&79.1\\9&&86.5\end{array}[/tex]