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Melinda and Paul shovel driveways and sidewalks in the winter as a way to earn extra money. Together they shoveled 450 square feet of sidewalk in 30 minutes. Then Melinda shoveled for 20 minutes while Paul shoveled for 25 minutes to complete 345 square feet of driveway. 30x + 30y = 450 20x + 25y = 345 How much more can Paul shovel in 1 minute than Melinda? 3 square feet per minute 6 square feet per minute 9 square feet per minute 15 square feet per minute

Answers

Answer 1
30x + 30y = 450 20x + 25y = 345

Here 345 represents the total area (in sq ft) shoveled; x repres. Melinda's rate and y represents Paul's rate.  We need to solve for x and y and then subtract the smaller from the larger.

30x + 30y = 450   Multiply this eqn by 2:      60x + 60y = 900
20x + 25y = 345   Mult this eqn by -3:          -60x -75y  = -1035
                                                                    ---------------------------
                                                                              -15y  = -135
                                                                                    y = 9

This comes to 9 square feet per minute.
Now, let's find x:    30x + 30y = 450; 30x + 270 = 450; 30x = 180; x = 6

Melinda can shovel 6 sq ft in 1 min, whereas Paul can shovel 9.

The difference is (9 - 6) sq ft / min,     or     3 sq ft / min   (answer)
Answer 2
3 square feet for edgenuity

Related Questions

[tex]F(x)=(6 \sqrt{x} -2)(5 \sqrt{x} +7)[/tex]

Answers

[tex]\bf f(x)=(6\sqrt{x}-2)(5\sqrt{x}+7) \\\\\\ \cfrac{dy}{dx}=\stackrel{product~rule}{\left( 6\cdot \frac{1}{2}x^{-\frac{1}{2}} \right)(5x^{\frac{1}{2}}+7)~~+~~(6x^{\frac{1}{2}}-2)\left(5\cdot \frac{1}{2}x^{-\frac{1}{2}} \right)} \\\\\\ \cfrac{dy}{dx}=\left(\cfrac{6}{2}\cdot \cfrac{1}{\sqrt{x}} \right)(5x^{\frac{1}{2}}+7)~~+~~2(3x^{\frac{1}{2}}-1)\left(\cfrac{5}{2}x^{-\frac{1}{2}} \right)[/tex]

[tex]\bf \cfrac{dy}{dx}=\left(3\cdot \cfrac{1}{\sqrt{x}} \right)(5x^{\frac{1}{2}}+7)~~+~~2\cdot \cfrac{5}{2}(3x^{\frac{1}{2}}-1)\left(\cfrac{1}{\sqrt{x}} \right) \\\\\\ \cfrac{dy}{dx}=\cfrac{3(5\sqrt{x}+7)}{\sqrt{x}}~~+~~\cfrac{5(3\sqrt{x}-1)}{\sqrt{x}}\\\\\\ \cfrac{dy}{dx}=\cfrac{15\sqrt{x}+21~~+~~15\sqrt{x}-5}{\sqrt{x}} \\\\\\ \cfrac{dy}{dx}=\cfrac{30\sqrt{x}+16}{\sqrt{x}}[/tex]

on the blueprint of the house 44 millimeters represents 8 meters. the length of the living room is 33 millimeters on the blueprint. what is the actual length of the living room?

Answers

So if 44=8 and 33=x, solve for x. 
The problem would look like this : 44mm = 8m
                                                      33mm =  x
You would cross multiply giving you this : 44x = 264
Then divide 264 by 44 to isolate x, then you should get this : x = 6
6m will be your answer.

The actual length of the living room is 6 meters.

What is unit conversion?

Conversion of units is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors.

Here the unit of lengths, millimeter is converted to meter based on the given scale

For the given situation,

In blue print the house is represented as follows,

44 millimeters =  8 meters

⇒ [tex]1 millimeter = \frac{8}{44} meters[/tex]

⇒ [tex]1 millimeter = 0.18 meters[/tex]

The length of the living room = 33 millimeters

The actual length of the living room in meters = [tex]33(0.18)[/tex]

⇒ [tex]5.94[/tex] ≈ [tex]6 meters[/tex]

Hence we can conclude that the actual length of the living room is           6 meters.

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Suppose there is a strong positive correlation between v and w. Which of the following must be true?

Answers

The truth is when V increases, W tends to increase. Positive correlation between two variables in which both variables move in tandem. Positive correlation exists when one variable decreases as the other also decreases or one variable increases while others increase too.

if it is a square is it a quadrilateral

Answers

Yes  a square is a type of quadrilateral  ( quadrilateral means 'four sides').
Yes, a square is a quadrilateral. It has all four equal sides and for equal 90-degree angles.

If (3,6) is a point on the graph of y=f(x) , what point must be on the graph of y=f(-x)? Explain.

Answers

The function y = f(-x) has the points (-3,-6).

When we substitute -x into a function f(x) to get f(-x), we are essentially reflecting the graph of f(x) across the y-axis. This is because replacing x with -x negates the x-values, effectively flipping the function horizontally.

Given that (3, 6) is a point on the graph of y = f(x), if we substitute -3 for x in f(-x), we get:

[tex]\[ f(-(-3)) = f(3) \][/tex]

So, the corresponding point on the graph of [tex]\(y = f(-x)\)[/tex] is [tex]\((3, 6)\)[/tex] since the function values stay the same when we reflect across the y-axis. Therefore, the point [tex](-3, -6)\)[/tex] is on the graph of [tex]\(y = f(-x)\)[/tex].

Graph the line for y+1=−35(x−4) on the coordinate plane. What are the coordinates that's all I need to know

Answers

y+1=−35(x−4)
lets get "y"on its own      
so 
y+1=−35(x−4)
y + 1 - 1 = −35(x − 4) - 1
y = -35(x-4) -1
y = -35x + (-35 * -4) - 1
y = -35x + 104 - 1
y = -35x + 103   (Enter this into your calculator)


(0, 103 and 2.943, 0)


(and I will not only give someone the answer, I will always explain it so that you know how to do it)

The length of a rectangle is 4 meters less than twice the width. If the area of the rectangle is 286 square​ meters, find the dimensions.

Answers

essentially, you have A=bw for a rectangle.
286=x(2x-4), let width be x.
solve
286=2x^2-4x for x

The dimensions of the rectangle are length = 22 meters and width = 13 meters

What is area of rectangle?

[tex]A=l\times w[/tex], where 'l' is the length and 'w' is the width of the rectangle.

For given question,

Suppose 'l' is the length and 'w' is the width of the rectangle.

The length of a rectangle is 4 meters less than twice the width.

So, we get an equation,

⇒ l = 2w - 4

The area of the rectangle is 286 square​ meters.

⇒ A = 286 sq. m.

Using the formula for the area of the rectangle,

[tex]\Rightarrow A=l\times w\\\\\Rightarrow 286=(2w-4)\times w\\\\\Rightarrow 286=2w^2-4w\\\\\Rightarrow 2w^2-4w-286=0[/tex]

Now, we solve the quadratic equation [tex]2w^2-4w-286=0[/tex]

[tex]\Rightarrow 2w^2-4w-286=0\\\\\Rightarrow w^2-2w-143=0\\\\\Rightarrow (w-13)(w+11)=0\\\\\Rightarrow w-13=0~~~or~~~w+11=0\\\\\Rightarrow w=13~~~or~~~w=-11[/tex]

w = -11 is not possible.

So, the width of the rectangle is 13 meters.

And the length of the rectangle would be,

[tex]\Rightarrow l \\= 2w - 4\\=(2\times 13)-4\\=22[/tex]

Therefore, the dimensions of the rectangle are length = 22 meters and width = 13 meters

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A farmer has 260 feet of fencing to make a rectangular corral. What dimensions will make a corral with the maximum area? What is the maximum area possible?

Answers

Suppose we have a rectangle with a side of length L and another side of length (L-x). The area of the rectangle is
[tex]A=L(x-L)=Lx-L^2[/tex]
We impose the condition of maximum
[tex]dA/dL =0[/tex]
Thus [tex]x-2L=0[/tex]   
[tex]x=2L[/tex]
Hence the maximum area is when we have a square
[tex]A =L(2L-L) =L^2[/tex]
With a perimeter [tex]P=4L[/tex] we obtain [tex]L=P/4 =260/4=65 feet[/tex]
which gives A =L^2=65*65 =6225 ft^2


For each of the following functions, find the maximum and minimum values of the function on the circular disk: x^2+y^2≤1. Do this by looking at the level curves and gradients.
f(x,y)=x+y+4
maximum value =

Answers

The gradient of the level curve f(x,y) can be found using partial derivatives.

[tex]\Delta f = (\frac{\delta f}{\delta x},\frac{\delta f}{\delta y}) = (1,1)[/tex]

This means that the max value lies on the vector <1,1> which is equivalent to the line y = x.

Find the points along edge of disc where y = x.

[tex]x^2 + y^2 = 1, y = x \\ \\ x^2 = \frac{1}{2} \\ \\ x = \pm \frac{\sqrt{2}}{2} [/tex]

These 2 solutions provide both max and min values.

Let x be positive will give max value for f(x,y)

[tex]f(x,y)_{max} = \frac{\sqrt{2}}{2} + \frac{\sqrt{2}}{2} + 4 = \sqrt{2} + 4 [/tex]
Final answer:

To find the maximum and minimum values of the function f(x, y) = x + y + 4 on the circular disk x^2 + y^2 ≤ 1, evaluate the function at the boundary of the disk.

Explanation:

To find the maximum and minimum values of the function f(x, y) = x + y + 4 on the circular disk x^2 + y^2 ≤ 1, we can use the method of level curves and gradients.

First, find the gradient of the function f(x, y) using partial derivatives.Next, find the critical points of the function by setting the gradient equal to zero and solving for x and y.Finally, evaluate the function at the critical points and the boundary of the circular disk to find the maximum and minimum values.

In this case, since the function f(x, y) = x + y + 4 is linear, it does not have any critical points. Therefore, the maximum and minimum values of the function on the circular disk x^2 + y^2 ≤ 1 are obtained by evaluating the function at the boundary of the disk.

When x^2 + y^2 = 1, the function value is largest at the point (x, y) = (-1, 0), giving a maximum value of -1 + 0 + 4 = 3. The function value is smallest at the point (x, y) = (1, 0), giving a minimum value of 1 + 0 + 4 = 5.

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Which numbers are a distance of 4 units from 7 on the number line? A number line ranging from negative 3 to 15. Select each correct answer.

3

11

7

15

4

−3

Answers

If the number line is drawn carefully and accurately, then the 3 and the 11 are both 4 units away from the 7 .

The 3 is on one side of it, and the 11 is on the other side.

Answer: 3, 11

Step-by-step explanation:

As u see in this screen shot there is wrongs and rights

Out of 6 women would consider themselves baseball​ fans, with a standard deviation of

Answers

For example 35% of women consider themselves fans of proffesional baseball You randonly selected six women and ask each if she considers herself a fan of proffesional baseball. Construct a binomial distribution using n = 6 and p = .35 P(x = 0) = 0.65^6 P(x = 1) = 6*0.35*0.65^5 P(x = 2) = 6C2*0.35^2*0.65^4 P(x = 3) = 6C3*0.35^3*0.65^3 etc.

Find the unit rate by using WKU. David drove 135 miles in 3 hours.

Answers

divide 135 by 3 and the unit rate will be 45

225/400 in simplest form

Answers

The simplified expression of 225/400 is 9/16

How to simplify the expression

From the question, we have the following parameters that can be used in our computation:

225/400

Divide 225 and 400 by 25

so, we have the following representation

225/400 = 9/16

This cannot be further simplified

Hence, the simplified expression is 9/16

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The intelligence quotient (iq) test scores are normally distributed with a mean of 100 and a standard deviation of 15. what is the probability that a person would score 130 or more on the test?

Answers

                                                        x - 100
Calculate the relevant z-score = ----------------
                                                             15
                            130-100              30
Here, this is z = ----------------- = ----------- = 2
                                     15               15

130 would be 2 std. dev. above the mean here.  

Your job would be to calculate the area under the std. normal curve to the right of z = 2.  Using my TI-83 Plus calculator's built-in normalcdf( function, I found that this probability is 1.00 - 0.977    =    0.023.

The length of a rectangle is twice its width. The perimeter is 60 ft. Find its area.

Answers

Answer:

200 feet squared

Step-by-step explanation:

W=Width

2W=Length

Perimeter = 2*Length + 2*Width

Now use substitution for the Length

60 = 2(2W) + 2(W)

60=4W + 2W = 6W divide both sides by 6

60/6 = 6W/6

10 = W

Width = 10 and Length is twice as long so it is 20. 10+10+20+20=60

The area is Length * Width = 20*10=200

solve each equation over [0,2pi)
4cos^4x-13cos^2x+3=0

Answers

[tex]\bf 4cos^4(x)-13cos^2(x)+3=0\impliedby \textit{notice, is really just a quadratic} \\\\\\ 4[~~[cos(x)]^2~~]^2-13[cos(x)]^2+3=0 \\\\\\\ [4cos^2(x)-1][cos^2(x)-3]=0\\\\ -------------------------------\\\\ 4cos^2(x)-1=0\implies 4cos^2(x)=1\implies cos^2(x)=\cfrac{1}{4} \\\\\\ cos(x)=\pm\sqrt{\cfrac{1}{4}}\implies cos(x)=\pm\cfrac{\sqrt{1}}{\sqrt{4}}\implies cos(x)=\pm\cfrac{1}{\sqrt{2}}[/tex]

[tex]\bf cos(x)=\pm\cfrac{\sqrt{2}}{2}\implies \measuredangle x= \begin{cases} \frac{\pi }{4}\\\\ \frac{3\pi }{4}\\\\ \frac{5\pi }{4}\\\\ \frac{7\pi }{4} \end{cases}\\\\ -------------------------------\\\\ cos^2(x)-3=0\implies cos^2(x)=3\implies cos(x)=\pm\sqrt{3} \\\\\\ cos(x)\approx \pm 1.7[/tex]

now, recall that, cosine for any angle has a range from -1 to 1, anything beyond that, is an invalid value, thus certainly 1.7 is so.  Meaning, there's no such angle(s) for the second root.

Simplify the expression where possible. (r 3) -2

Answers

What you do to on side of an equation (=) you must do to the other to keep both sides equal.

r3-2+2=+2  (add 2 to both sides of the equation to simplify the left side)
which becomes
r3=2
r3/3 = 2/3 (divide both sides by 3) Note 3/3 =1 and 1 r is the same as r
which becomes
r=2/3 .

Write the following comparison as ratio reduced to lowest terms 194 inches to 17 feet

Answers

if you put it in fraction form and use PEMDAS to find the answer

Beyond Euclidean Geometry.


Many airlines use maps to show the travel paths of all their flights, which are called route maps. For instance, K12Air has a route map that describes all the possible routes to and from Samsville, Shiloh, Camden, Chelsea, Jamestown, and Lorretta.

You have been provided a route map for K12Air. Write a question about this map that involves Hamiltonian or Euler circuits or paths.

Help me come up with a question?

Answers

An Euler path is a path that traverses every edge (line) exactly once.
In the given graph, each edge (line) represents a given flight for the aircraft.  The pilot has to figure out a path to ensure each given flight is fulfilled (without repetition). 
An Euler circuit, is an Euler path that returns to the original position.  For this graph, there is no such circuit, but an Euler path exists.
The return flight will be another path in the opposite direction.

A Hamiltonian path is a path that touches on each node (city) exactly once, edges may be skipped or repeated.  This way, the pilot makes a stop at each city exactly once (without repetition of the city).
A Hamiltonian circuit is a path that touches on each intermediate city exactly once, but returns to the original city.
There are possible Hamiltonian paths and Hamiltonian circuits in this graph.

The above explanations should give you a clear idea on what questions to ask.

A suitable question to ask about the K12Air route map in the context of Hamiltonian or Euler circuits or paths could be:

Is it possible to find a Hamiltonian circuit on the K12Air route map that allows a plane to travel through each city exactly once before returning to the starting city?

To formulate a question involving Hamiltonian or Euler circuits or paths, one must understand the difference between these concepts:

- A Hamiltonian path is a path in an undirected or directed graph that visits each vertex exactly once. If this path returns to the starting vertex, it is called a Hamiltonian circuit.

- An Euler path is a path in a graph that visits every edge exactly once. If this path starts and ends at the same vertex, it is called an Euler circuit.

Given the context of the K12Air route map, which describes all the possible routes to and from various cities, the question should focus on whether it's possible to traverse the graph representing the route map in a way that satisfies the conditions of either a Hamiltonian or an Euler circuit/

For the Hamiltonian circuit, the question is whether there exists a sequence of flights that allows a plane to start at one city, visit every other city exactly once, and return to the starting city without repeating any city. This would require the route map to have a Hamiltonian circuit, which is a more stringent condition than an Euler circuit because it involves visiting all vertices exactly once.

For an Euler circuit, the question would be whether there exists a sequence of flights that allows a plane to traverse every possible route exactly once before returning to the starting point. This would require the route map to have an Euler circuit, meaning every edge (route) is used exactly once.

In the case of K12Air, the question about the Hamiltonian circuit is particularly interesting because it tests the connectivity of the route map and the possibility of a round trip that covers all cities without repetition. This could be relevant for planning efficient travel itineraries or for optimizing the use of airline resources. If the route map does not allow for a Hamiltonian circuit, one might then ask if a Hamiltonian path exists, which would not require returning to the starting city.

To answer such a question, one would need to analyze the connectivity of the graph represented by the route map, possibly using theorems related to Hamiltonian graphs, such as Dirac's theorem or Ore's theorem, which provide sufficient conditions for a graph to contain a Hamiltonian circuit.

if the smaller of two consecutive even intergers is subtracted from 3 times the larger the result is 42

Answers

two consecutive even integers are x and x + 2
3(x + 2) - x = 42
3x + 6 -x = 42
2x = 36
  x = 18
answer
smaller number: 18
bigger number: 18 + 2 = 20

If the apy of a savings account is 3.7%, and if the principal in the savings account were $3600 for an entire year, what will be the balance of the savings account after all the interest is paid for the year?

Answers

that would be   A = P (1+r)^t, where P is the initial amount and r is the annual interest rate.  For 1 year, t = 1.

Then A = $3600(1+0.037)^1 = $3733.20, including interest.

Find the value of kk for which the constant function x(t)=kx(t)=k is a solution of the differential equation 3t3dxdt+5x−3=03t3dxdt+5x−3=0.

Answers

If [tex]x(t)=k[/tex] is constant, then [tex]\dfrac{\mathrm dx}{\mathrm dt}=0[/tex], so you have

[tex]5k-3=0\implies k=\dfrac35[/tex]

which of the fallowing functions has a slope 3/2 and contains the midpoint segment between (6, 3) and (-2, 11)?

Answers

well, we know the slope is 3/2, what's the midpoint of those anyway?

[tex]\bf \textit{middle point of 2 points }\\ \quad \\ \begin{array}{lllll} &x_1&y_1&x_2&y_2\\ % (a,b) &({{ 6}}\quad ,&{{ 3}})\quad % (c,d) &({{ -2}}\quad ,&{{ 11}}) \end{array}\qquad % coordinates of midpoint \left(\cfrac{{{ x_2}} + {{ x_1}}}{2}\quad ,\quad \cfrac{{{ y_2}} + {{ y_1}}}{2} \right) \\\\\\ \left( \cfrac{-2+6}{2}~~,~~\cfrac{11+3}{2} \right)\implies (2,7)[/tex]

so, what's the equation of a line whose slope is 3/2 and runs through 2,7?

[tex]\bf \begin{array}{lllll} &x_1&y_1\\ % (a,b) &({{ 2}}\quad ,&{{ 7}}) \end{array} \\\\\\ % slope = m slope = {{ m}}= \cfrac{rise}{run} \implies \cfrac{3}{2} \\\\\\ % point-slope intercept \stackrel{\textit{point-slope form}}{y-{{ y_1}}={{ m}}(x-{{ x_1}})}\implies y-7=\cfrac{3}{2}(x-2) \\\\\\ y-7=\cfrac{3}{2}x-3\implies y=\cfrac{3}{2}x+4[/tex]

A 250-kVA, three-phase, 480-volt transformer requires 75 gallons of insulating oil to keep it properly cooled. How many liters is this?

Answers

This problem can be directly solved by using a conversion factor. Simple research will tell us that 1 gallon contains about 3.78 Liter. Therefore the volume in Liter is:

volume = 75 gallons * (3.78 Liter / gallon)

volume = 283.5 Liters

Ms. Rios buys 453 grams of strawberries she has 23 grams left after making smoothies how many grams of strawberries did she use

Answers

453 - 23 = 420 grams left
Final answer:

Ms. Rios used 430 grams of strawberries to make her smoothies. This is calculated by subtracting the amount left (23 grams) from the total amount purchased (453 grams).

Explanation:

To determine how many grams of strawberries Ms. Rios used for making smoothies, we can subtract the quantity of strawberries left unprocessed from the total quantity she originally purchased. In this case, Ms. Rios bought 453 grams of strawberries and had 23 grams left after making smoothies.

The formula to determine the solution would be: Total amassed quantity - Remaining quantity = Used quantity

By filling the above formula with our values, the solution will be as follows: 453 grams (total) - 23 grams (remaining) = 430 grams (used).

Thus, Ms. Rios used 430 grams of strawberries for making smoothies.

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Zeno has to go a distance, d, to get to his destination. He claims he can never get there because he has to travel half that distance d, then half of half of distance d, and so on. He says that he has to do an infinite number of tasks and that it is impossible. Use an infinite geometric series to help Zeno. Identify a1 and r to form the infinite geometric series that represents the problem.

Answers

a1=1/2d

r=1/2

sup it needs twenty character apparently

The [tex]a_{1} =\frac{d}{2}[/tex]  and [tex]r=\frac{1 }{2 }[/tex] are for the infinite Geometric sequence.

What is geometric sequence  ?

Geometric sequence a sequence of non-zero numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.

i.e. [tex]a+ar+ar^2+ar^3+......[/tex]

Here, [tex]a=[/tex] First term and [tex]r=[/tex] common ratio

Next term formula, [tex]a_{n} =a_{1}\ *\ r^{n-1}[/tex]

We have,

[tex]d=[/tex] distance to her destination,

Now,

According to the question;

Zeno has to travel half that distance i.e. [tex]\frac{d}{2}[/tex],

Then half of half of distance i.e. [tex]\frac{d}{4}[/tex],

Then half of [tex]\frac{d}{4}[/tex] distance i.e. [tex]\frac{d}{8}[/tex]  and so on.

So,

Here, we have,

[tex]\frac{d}{2},\frac{d}{4},\frac{d}{8}, .........[/tex]

So,

We have Geometric Sequence,

Here,

[tex]a_{1} =\frac{d}{2}[/tex] and

Now,

[tex]r=[/tex] common ratio,

[tex]r=\frac{a_{2} }{a_{1} }[/tex]

[tex]r=\frac{\frac{d}{4} }{\frac{d}{2} }[/tex]

We get,

[tex]r=\frac{1 }{2 }[/tex]

So, These are [tex]a_{1} =\frac{d}{2}[/tex]  and [tex]r=\frac{1 }{2 }[/tex] of the Geometric sequence.

Hence, we can say that he [tex]a_{1} =\frac{d}{2}[/tex]  and [tex]r=\frac{1 }{2 }[/tex] are for the infinite Geometric sequence.

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Yearbook sales this year increased 120% over last years yearbook sales. If 465 yearbooks were sold last year, how many were sold this year?

Answers

First turn the percent into a decimal. It would be 1.20.
Multiply 465 and 1.20.
465 x 1.20=558
Then add 465 and 588 to get the final amount.
465+558=1023
There were 1,023 yearbooks sold this year.

Answer:

This year 1,023 books were sold.

Step-by-step explanation:

Last year the number of yearbooks were sold = 465

This year sales are increased 120% over last years sales.

this year sale = 465 + (120% of 465)

                      = 465 + ([tex]\frac{120}{100}[/tex] × 465)

                     = 465 + (1.2 × 465)

                     = 465 + 558

                     = 1,023 books

This year 1,023 books were sold.

The sat scores have an average of 1200 with a standard deviation of 60. a sample of 36 scores is selected. what is the probability that the sample mean will be larger than 1224? round your answer to three decimal places.

Answers

Final answer:

The probability that the sample mean of SAT scores will be larger than 1224 is 0.008. This is calculated using the z-score, which in this case is 2.4 after determining the standard error of the sampling distribution.

Explanation:

To find the probability that the sample mean will be larger than 1224, we will use the concept of the sampling distribution of the sample mean. Given the population mean (μ) is 1200 and standard deviation (σ) is 60, and that the sample size (n) is 36, the standard deviation of the sampling distribution, known as the standard error (SE), is

σ/√n = 60/√36 = 10.

We calculate the z-score for the sample mean of 1224 using the formula

z = (X - μ)/SE = (1224 - 1200)/10 = 2.4

A z-score of 2.4 indicates that the sample mean is 2.4 standard errors above the population mean.

To find the probability associated with this z-score, we refer to the normal distribution table or use a calculator. The probability to the left of z = 2.4 is 0.9918. Therefore, the probability that the sample mean is greater than 1224 is

1 - 0.9918 = 0.0082

which can be rounded to three decimal places as 0.008.

In one year, Michael earned $6300 as a work study in college. He invested part of the money at 9% and the rest at 7%. If he received a total of $493 in interest at the end of the year, how much was invested at 7%? How much was invested 9%?

Answers

He invested x at 9% and y at 7%.
The total investment was $6300, so
x + y = 6300

The 9% account earned 0.09x in interest.
The 7% account earned 0.07y in interest.
The total interest earned was
0.09x + 0.07y = 493

We have 2 equations in 2 unknowns. We solve the equations as a system of equations.

Solve the first equation for x and substitute in the second equation.

x = 6300 - y

0.09(6300 - y) + 0.07y = 493

567 - 0.09y + 0.07y = 493

-0.02y = -74

y = 3700

x + y = 6300

x + 3700 = 6300

x = 2600

He invested $2600 at 9% and 3700 at 7%

Two trains arrived at a station at 2:55 P.M., with one arriving on Track A, and the other arriving on Track B. Trains arrive on Track A every 16 minutes, and they arrive on Track B every 18 minutes. At what time will trains next arrive at the same time on both tracks? A) 4:07 P.M. B) 5:19 P.M. C) 6:31 P.M. D) 7:43 P.M.

Answers

the time before  they will arrive together next is given by the LCM of 16 and 18 which is 144 minutes
2:55 PM + 2 h 24 minutes = 5.19 PM

Its B
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