Answer:
5 p.m.
Step-by-step explanation:
Newton's law of cooling-
[tex]T(t)=t_a+(t_0-t_a)e^{-kt}[/tex]
where,
[tex]t_0[/tex] = the initial temp. = 98.6 F (human body temp.)
k = 0.1947,
T(t) = 66 F,
[tex]t_a[/tex] = 55 F,
Putting the values,
[tex]\Rightarrow 66=55+(98.6-55)e^{-0.1947\cdot t}\\\\\Rightarrow 66=55+(43.6)e^{-0.1947\cdot t}\\\Rightarrow (43.6)e^{-0.1947\cdot t}=11\\\Rightarrow e^{-0.1947\cdot t}=\dfrac{11}{43.6}=0.2523\Rightarrow \ln e^{-0.1947\cdot t}=\ln 0.2523\\\Rightarrow -0.1947\cdot t\times \ln e=\ln 0.2523\\\Rightarrow -0.1947\cdot t\times 1=\ln 0.2523\\\Rightarrow t=\dfrac{\ln 0.2523}{-0.1947}\\\Rightarrow t=7\ h[/tex]
Therefore, the time of death was 7 hours before midnight i.e at 5 pm.
Solve:
-9(-5-3x)=21
A) 8/9
B) -8/9
C) 22/9
D) -22/9
Answer: B) -8/9
Step-by-step explanation:
I would start by looking inside the parenthesis to see if anything could be simplified. We see the terms -5 and -3x, and upon realizing that there is no way to simplify, we can go ahead and just simplify the left side of the equation as much as we can before worrying about breaking the equation down. Distribute the -9 to the -5 and the -3x (multiply -9 by -5 and -9 by -3x). Multiplying two negative numbers will result in a positive value, so the left side of your equation should end up looking like this: 45+27x=21. Now, we can start working to get the variable on its own. Subtract 45 from both sides of the equation. On the left side this cancels out and leaves you with 27x. On the right side you have more of the negative value than positive value, so you end up with -24. The equation now looks like this: 27x=24. The only thing left to do is divide the equation by 27. On the left side of the equation, this leaves you with just x. On the right side, you get -24/27. Normally at this point I would divide out to get the decimal form (I prefer working with decimals) but bc the answer choices are all fractions there's not really a good use to, so instead let's just find the greatest common denominator (GCD) which would be 8. (Just as a clarification the GCD is the largest number you can divide both numbers by evenly.) Divide both the numerator and denominator by eight leaves you with -8/9. Therefore, x= -8/9.
The train holds 66 passengers.
It starts out empty.
It picks up 1 passenger at the first station, 2 passengers at the second station, 3
passengers at the third station, and so on.
No one gets off.
After how many stations will the train be full?
Answer:
1,2,3,4,5,6,7,8,9,10,11
3 + 7 + 11 + 15 + 19 + 11
10 + 26 + 19 + 11
55 + 11 = 66
11 stations
Hope this helps
Step-by-step explanation:
Answer:
11 stations.
Step-by-step explanation:
1st stop = 1
2nd stop 1+2=3
3rd stop 3+3=6
4th stop 6+4=10
5th stop 10+5=15
6th stop 15+6=21
7th stop 21+7=28
8th stop 28+8=36
9th stop 36+9=45
10th stop 45+10=55
11th stop 55+11=66
What is the simplified form of this expression?
Answer:
B. -7[tex]x^{2}[/tex] + 3x + 5
Step-by-step explanation:
(-3[tex]x^{2}[/tex] + x + 5) - (4[tex]x^{2}[/tex] - 2x)
-3[tex]x^{2}[/tex] + x + 5 - 4[tex]x^{2}[/tex] - 2x
Combine like terms
-3[tex]x^{2}[/tex] - 4[tex]x^{2}[/tex] = -7[tex]x^{2}[/tex]
x - -2x = x + 2x = 3x
5
-7[tex]x^{2}[/tex] + 3x + 5
I hope this helps :))
write in algebraic expression to find the number of seconds in n minutes
Find the gradient of the line segment between the points (-5,-2) and (-3,-8)
Answer:
- 3
Step-by-step explanation:
Calculate the gradient (slope) m using the slope formula
m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
with (x₁, y₁ ) = (- 5, - 2) and (x₂, y₂ ) = (- 3, - 8)
m = [tex]\frac{-8-(-2)}{-3-(-5)}[/tex] = [tex]\frac{-8+2}{-3+5}[/tex] = [tex]\frac{-6}{2}[/tex] = - 3
If the regular recipe that makes 14 pancakes calls for 1 cup of milk, how many cups should I use to make 21 pancakes? Group of answer choices 1 cup 2 cups 0.5 cups 1.5 cups
Answer:
x = 1 1/2 cups
1.5 cups
Step-by-step explanation:
We can use ratios to solve
14 pancakes 21 pancakes
------------------ = ------------
1 cup x cups
Using cross products
14x = 21*1
Divide each side by 14
14x/14 = 21/14
x = 3/2
x = 1 1/2 cups
Which graph is the result of reflecting f(x) = One-fourth(8)x across the y-axis and then across the x-axis?
HELP! Which of the following are interior angles in the figure below? PLEASEEE!!!!! URGENT dont need to explain
I have a box of 24 different types of cup cakes. 1⁄2 of the cupcakes are vanilla. 1⁄8 of the cupcakes are strawberry. And the rest of the cupcakes are chocolate. How many of each type of cupcake do we have?
Answer:
21 7/8 is choclate
1/2 or 2 is vanilla
1/8 is strawberry
Step-by-step explanation:
1/2 x 4 is is 2
1/8 < 2
2 of the cupcakes (into eights) are vanilla from which a dominatorof 8
2 plus 1/8 is 2 1/8
24 - 2 1/8 is 21 7/8
Please help with this question
Answer:
2nd graph from top
Step-by-step explanation:
a/ -5 ≥ 10
Multiply each side by -5, remembering to flip the inequality
a/-5 *-5 ≤ 10*-5
a ≤ -50
closed circle at -50 line going to the left
plz help me w this!!! lowkey forgot how to do it lol. marking brainiest aswell!!!
Answer:
B
Step-by-step explanation:
A = 1/2π * r²
A/(1/2π) = r² (Divide by 1/2π)
r = √(2A/π) (Take the square root of both sides then simplify)
Answer:
B. r=[tex]\sqrt{\frac{2A}\pi}}[/tex]
Step-by-step explanation:
First multiply both sides by 2. This gives us 2A=[tex]\pi[/tex]r². Now, divide both sides by [tex]\pi[/tex]. Now we have [tex]\frac{2A}{\pi}[/tex]=r². Now, square root both sides. The final answer is r=[tex]\sqrt{\frac{2A}{\pi}}[/tex]
Which number produces a rational number when added to 5/8 ?
A. 0.777....
B. 5/6
C. 0.13241536...
D. -0.625
Answer:
option c is correct
Step-by-step explanation:
please mark me brainlest
please thanks
Answer:
Step-by-step explanation:
Answer is C. 0.132
1. A U.S. student studied abroad in Zürich, Switzerland. When he arrived in Zürich in January 2005, he exchanged $20,000 for Swiss francs when the exchange rate of USD/CHF (U.S. dollars to Swiss francs) was 1.15. When he left Zürich in January 2006, the exchange rate was 1.30. If he had started his year abroad in January 2006 instead of January 2005, would he have gotten more or fewer francs? What is the exact difference?
Answer:
Yes
With an extra 3000CHF
Step-by-step explanation:
In year 2005, the exchange rate was 1$ = 1.15CHF
The student came in with $20,000.
The amount he had in CHF(swiss franc) = ?
$1 = 1.15C
$20,000 = x CHF
X = (20000 × 1.15) / 1
X = 23,000CHF
When he came to Zürich in 2005, he has 23,000 swiss franc.
But the exchange rates changed in 2006 to C1.30 against the dollar.
$1 = 1.30CHF
$20,000 = xCHF
X = 26,000CHF
In 2006, he would've had 26,000CHF.
The difference between what he would've had in 2006 against 2005 is
26,000CHF - 23,000CHF = 3000CHF
He would've had an extra 3000CHF if he came in the year 2006.
Anyone know how this can be solved?
Answer:
127.235cm^2
Step-by-step explanation:
A = πr²/2 = 40.5 * π [cm²] ≈ 127.235 [cm²]
Answer:
[tex]127.251 {cm}^{2} [/tex]
Step-by-step explanation:
[tex] \frac{180}{360} \times \pi {r}^{2} \\ \frac{1}{2} \times 3.142 \times 9 \times 9 \\ = \frac{254.502}{2} \\ = 127.251 {cm}^{2} [/tex]
hope this helps
brainliest appreciated
good luck! have a nice day!
evaluate 1/2^-2x^-3y^5
A) -1/32
B) 16
C) -16
D)-4
Answer:
To answer this question you need to x and y
Step-by-step explanation:
18x+30=6(2x-1). What is a first step to isolate the variable there can be more than one answer A. Subtract 30 from 18x +30 B. Divide both sides by 6 C. Multiple both sides by 6 D. Multiple 2x-1 by 6
Answer:
Divide both sides by 6
or
Multiply 2x-1 by 6
Step-by-step explanation:
18x+30=6(2x-1).
Divide both sides by 6
18x/6+30/6=6/6(2x-1).
3x +5 = 2x-1 or
We could multiply 2x-1 by 6
18x+30 = 6(2x-1)
18x+30 = 12x-6
Answer:
D
Step-by-step explanation:
18x+30=6(2x-1)
My first step would be to distribute the 6 so that the next step you can subtract 30 from both sides.
3w + 4u - 6
Simplify
Step-by-step explanation:
There are many different ways to simplify this. It could be
3(w-2)+4u , 2(2u-3)+3w , or something else.
Which numbers are the extreme of the proportion shown below?
Answer:
4,35
Step-by-step explanation:
4/7 = 20/35
Converting it into ratio form
4:7 = 20:35
The Extremes of this proportion are 4,35
While, the means of this proportion are 7, 20
if a=10, What is a/ 2 plus 9
Answer:
a=14
Step-by-step explanation:
if a=10, 10/2 = 5 plus 9 = 14
Answer:
The anwer is 14
Step-by-step 1explanation:
10/2= 5 and 5 plus 9 is 14
Dos motos, A y B, toman la salida en una carrera de 90 km. La moto A realiza el recorrido con una velocidad media inferior en 20 km/h a la de la moto B, con lo que llega a la meta 3 minutos después que B. Calcula la velocidad de cada moto.
Answer:
motorcycle A: 180 km/h
motorcycle B: 200 km/h
Step-by-step explanation:
To solve this question we need to write a system of equations for A and B, using the equation:
distance = speed * time
The speed of A is 20 less than the speed of B, so:
speedA = speedB - 20
And the time A traveled is 3 minutes (0.05 hours) more than B's time, so:
timeA = timeB + 0.05
Then, using the distance equation, we have that:
distanceB = speedB * timeB
90 = speedB * timeB
distanceA = speedA * timeA
90 = (speedB - 20) * (timeB + 0.05)
90 = speedB * timeB + 0.05 * speedB - 20*timeB - 1
90 = 90 + 0.05 * speedB - 20*timeB - 1
20*timeB = 0.05 * speedB - 1
timeB = (speedB - 20)/400
using this timeB in the distance equation, we have:
90 = speedB * (speedB - 20)/400
90 * 400 = speedB^2 - 20*speedB
speedB^2 - 20*speedB - 36000 = 0
Solving this quadratic equation, we have speedB = 200 km/h
And the speedA is:
speedA = speedB - 20 = 200 - 20 = 180 km/h
Rickie played eight rounds of miniature golf in June and eight rounds of miniature golf in July. He recorded his score for each round. Rickie’s mother asked him if his scores varied more in June or July. Rickie claims that a measure of center will answer his mother’s question. Is Rickie’s claim correct?
Answer:
The measure of variability should be used.
Step-by-step explanation:
It is provided that Rickie played eight rounds of miniature golf in June and eight rounds of miniature golf in July. He recorded the cores for each round.
Now to determine in which month Rickie's score varied the most the measure of variability would be used and not measure of center.
This is because:
The Measures of Central tendency is a distinct value that describe a data set by recognizing the central location within that data set. The measures of central tendency are every so often are known as measures of central location. They are also known as summary statistics.
Whereas the measure of variability is used to determine the amount of variability in the data set. They represent how far the observations are from the center of the data set.
Thus, to answer his mother's question, the measure of variability should be used.
Help! I need to know if 7√3+2√9 is rational or irrational
Answer:
Irrational
Step-by-step explanation:
[tex]7\sqrt{3}+2\sqrt{9}= \\\\7\sqrt{3}+2(3)= \\\\6+7\sqrt{3}[/tex]
Therefore, this is irrational. Hope this helps!
Gas mileage actually varies slightly with the driving speed of a car (as well as with highway vs. city driving). Suppose your car averages 26
miles per gallon on the highway if your average speed is 45
miles per hour, and it averages 18
miles per gallon on the highway if your average speed is 65
miles per hour. Answer parts (a) and (b) below.
a. What is the driving time for a 2500
-mile
trip if you drive at an average speed of 45
miles per hour? What is the driving time at 65
miles per hour?
Answer:
Step-by-step explanation:
Suppose the car mileage actually varies slightly with the driving speed of the car
Suppose your car averages 26 miles per gallon on the highway if your average speed is 45 miles per hour,
and it averages 18 miles per gallon on the highway if your average speed is 65 miles per hour.
The driving time for a 2500-mile trip if you drive at an average speed of 54 miles per hour
[tex]= \frac{Distance}{Speed} = \frac{2500 }{45} \\\\= 55.56 hours.[/tex]
The driving time for a 2500-mile trip if you drive at an average speed of 65 miles per hour
[tex]= \frac{Distance}{Speed} = \frac{2500 }{65} \\\\= 38.46 hours.[/tex]
Debbie buys a tree for the holidays. She would like to determine the amount of space it will take up in her living room. The tree is cone shaped and has a radius of 2 feet. Find the volume of the tree if it is in the shape of a cone and its height is two times its radius. The radius of a cone whose height is is equal to two times its radius is given as: r equal to cube root of (3V/4π)
Answer:
Volume of Cone =
[tex]= \frac{1}{3}\pi (2)^2 (4)\\\\=\frac{1}{3}(3.14)(4)(4)\\\\=\frac{1}{3}\times 3.14\times 16 \\\\=\frac{1}{3}\times50.24\\\\=16.746\\\\\approx16.75 \texttt {ft} ^3[/tex]
Thus, Volume = 16.75 cubic feet
Step-by-step explanation:
Volume of a cone is given by the formula
[tex]V=\frac{1}{3}\pi r^2 h[/tex]
Where r is the radius and
h is the height
Given radius r = 2 and
height is 2 times that.
So height is 2*2 = 4
Plugging these into the formula we get:
Volume of Cone =
[tex]= \frac{1}{3}\pi (2)^2 (4)\\\\=\frac{1}{3}(3.14)(4)(4)\\\\=\frac{1}{3}\times 3.14\times 16 \\\\=\frac{1}{3}\times50.24\\\\=16.746\\\\\approx16.75 \texttt {ft} ^3[/tex]
Thus, Volume = 16.75 cubic feet
Encontre o erro em cada uma das resoluções abaixo.
Answer:
I will answer this in English.
a) here you written 208 = (2^6)*3, while in the table you can see 5 times the number 2 and 2 times the number 3, this means that:
208 = 2^5*3^2
then we would have:
√208 = √(2^5*3^2) = 3*2*√2 = 6*√2
b) This time is correct that:
1568 = 2^5*7^2
but the simplification in the square root is not correct. (√(2^5) is not equal to 2^2)
as √(2^5*7^2) = √(2*2^4*7^2) = 2^2*7*√2 = 4*7*√2 = 28*√2
Holly made 12 pair of earrings for each of her girlfriends. To wrap the pairs individually, she creates a simple cardboard gift box to fold into a pyramid. The base is a square with side lengths 10c m. The sides are 4 equilateral triangles with side lengths 10 cm and height h. The height h is approximately 8 2/3 cm. In square centimeters, what is the minimum amount of cardboard Holly needs to create 12 gift boxes to wrap each pair of earrings individually?
Answer:
3280cm²
Step-by-step explanation:
We are told the gift box is folded into a Pyramid with a square base.
Hence, we are to find the Surface Area of a square pyramid
From the question, we are given:
Length of the base of the square = 10cm
Triangle
Side length = 10cm
Height = 8 2/3 cm
A square Pyramid has 5 faces: 4 triangles and 1 square.
Step 1
Find the Area of the square
Formula = Side length² this is because all the side of a square is equal.
Length of the base = 10cm
Area of the square = (10cm)²
= 100cm²
Step 2
Find the Area of the triangle. We are told the 4 triangles are equilateral, which means their side are equal.
Hence, for one triangle.
Area of a triangle = 1/2 × base × height
Base = side length = 10cm
Height = 8 2/3 = 8.6666666667cm
Area of a triangle = 1/2 × 10 × 8.6666666667
Area of a triangle = 43.333333333cm²
Since we have 4 triangles
We would have : 4 × 43.333333333cm²
= 173.33333333cm²
The Area of the 4 equilateral triangles =
173.33333333cm²
Step 3
The Surface area of the Square Pyramid
= Sum of the areas of all the faces.
= 100cm² + 173.33333333cm²
= 273.33333333cm²
Therefore, the minimum amount of cardboard needed to make one gift box = 273.33333333cm²
Step 4
The minimum amount of cardboard Holly needs to create 12 gift boxes to wrap each pair of earrings individually is calculated as: 12 × 273.33333333cm²
= 3280cm²
f(x) = x + 2
g(x) = x - 4
(f g)(x) =
0 2x- 2
O x² – 8
o x² – 2x- 8
o x² + 2x - 8
Answer:
(fg)(x) = x^2 -2x -8
Step-by-step explanation:
(fg)(x) = f(x)·g(x) = (x +2)(x -4)
= x(x -4) +2(x -4) = x^2 -4x +2x -8
= x^2 -2x -8 . . . . matches the 3rd choice
Need help ASAP! Need help ASAP will mark you as brainiest!
Answer:
[tex]r=\frac{44}{\pi }[/tex]
Step-by-step explanation:
[tex]88=2\pi r[/tex]
[tex]\mathrm{Switch\:sides}\\2\pi r=88\\\frac{2\pi r}{2\pi }=\frac{88}{2\pi }\\r=\frac{44}{\pi }\\or\\r=14.00563[/tex]
Answer:
2 metres
Step-by-step explanation:
Circumference = 2 × π × r
→ Substitute in the values
88 = 2 × [tex]\frac{22}{7}[/tex] × r
→ Divide both sides by 2 to isolate [tex]\frac{22}{7}[/tex] and r
44 = [tex]\frac{22}{7}[/tex] × r
→ Multiply everything by 7 to get rid of the fraction
308 = 22 × 7r
→ Divide the equation by 22 to isolate 7r
14 = 7r
→ Divide the equation by 7 to isolate r
2 = r
The radius of the circle with a circumference of 88 meters is 2 metres
Please if you know this please help me I’m stuck I don’t know
Answer:
The vertical angles theorem
Step-by-step explanation:
The Vertical Angles Theorem states that vertical angles, angles that are opposite each other and formed by two intersecting straight lines, are congruent.
Angles ∠JKN and ∠MKL fit the criteria of the vertical angles theorem, meaning they are congruent.
anyone know this please ;)
Answer:
The planet to have the biggest mass is Jupiter
the radius of mercury is 2.44 × 10^5
the difference in mass between Jupiter and Saturn is 2.2 × 10⁴
