I need help I just don't understand

Answer:

The probability is  [tex]P(\= X > x ) = 0.78814[/tex]

Step-by-step explanation:

From the question we are given that

     The population  mean is  [tex]\mu = 149[/tex]

     The standard deviation is  [tex]\sigma = 14[/tex]

     The random number    [tex]x = 147.81[/tex]

      The sample  size is  [tex]n = 88[/tex]

The probability that  the sample mean would be greater than [tex]P(\= X > x ) = P( \frac{ \= x - \mu }{\sigma_{\= x} } > \frac{ x - \mu }{\sigma_{\= x} } )[/tex]

Generally the z- score of this normal distribution is mathematically represented as

       [tex]Z = \frac{ \= x - \mu }{\sigma_{\= x} }[/tex]

Now

        [tex]\sigma_{\= x } = \frac{\sigma }{\sqrt{n} }[/tex]

substituting values

         [tex]\sigma_{\= x } = \frac{14 }{\sqrt{88} }[/tex]

         [tex]\sigma_{\= x } = 1.492[/tex]

Which implies that

         [tex]P(\= X > x ) = P( Z > \frac{ 147.81 - 149 }{ 1.492} )[/tex]

        [tex]P(\= X > x ) = P( Z > -0.80 )[/tex]

Now from the z-table  the  probability is  found to be

        [tex]P(\= X > x ) = 0.78814[/tex]

Step-by-step explanation:

In the fourth quadrant, the equation of the unit circle is:

y = -√(1 − x²), 0 ≤ x ≤ 1

The x and y coordinates of the centroid are:

cₓ = (∫ x dA) / A = (∫ xy dx) / A

cᵧ = (∫ y dA) / A = (∫ ½ y² dx) / A

For a quarter circle in the fourth quadrant, A = -π/4.

Solving each integral:

∫₀¹ xy dx

= ∫₀¹ -x √(1 − x²) dx

= ½ ∫₀¹ -2x √(1 − x²) dx

If u = 1 − x², then du = -2x dx.

When x = 0, u = 1.  When x = 1, u = 0.

= ½ ∫₁⁰ √u du

= ½ ∫₁⁰ u^½ du

= ½ (⅔ u^³/₂) |₁⁰

= (⅓ u√u) |₁⁰

= 0 − ⅓

= -⅓

∫₀¹ ½ y² dx

= ½ ∫₀¹ (1 − x²) dx

= ½ (x − ⅓ x³) |₀¹

= ½ [(1 − ⅓) − (0 − 0)]

= ⅓

Therefore, the x and y coordinates of the centroid are:

cₓ = (-⅓) / (-π/4) = 4/(3π)

cᵧ = (⅓) / (-π/4) = -4/(3π)

Answer:

The upper confidence bound for population mean escape time is: 379.27

The upper prediction bound for the escape time of a single additional worker  is 413.64

Step-by-step explanation:

Given that :

sample size n = 26

sample mean [tex]\bar x[/tex] =  371.08

standard deviation [tex]\sigma[/tex] = 24.45

The objective is to calculate an upper confidence bound for population mean escape time using a confidence level of 95%

We need to determine the standard error of these given data first;

So,

Standard Error S.E = [tex]\dfrac{\sigma }{\sqrt{n}}[/tex]

Standard Error S.E = [tex]\dfrac{24.45 }{\sqrt{26}}[/tex]

Standard Error S.E = [tex]\dfrac{24.45 }{4.898979486}[/tex]

Standard Error S.E = 4.7950

However;

Degree of freedom df= n - 1

Degree of freedom df= 26 - 1

Degree of freedom df= 25

At confidence level of 95% and Degree of freedom df of  25 ;

t-value = 1.7080

Similarly;

The Margin of error = t-value × S.E

The Margin of error = 1.7080 × 4.7950

The Margin of error = 8.18986

The upper confidence bound for population mean escape time is = Sample Mean + Margin   of  Error

The upper confidence bound for population mean escape time is =  371.08 +  8.18986

The upper confidence bound for population mean escape time is = 379.26986  [tex]\approx[/tex] 379.27

The upper confidence bound for population mean escape time is: 379.27

b.  Calculate an upper prediction bound for the escape time of a single additional worker using a prediction level of 95%.

The standard error of the mean = [tex]\sigma \times \sqrt{1+ \dfrac{1}{n}}[/tex]

The standard error of the mean = [tex]24.45 \times \sqrt{1+ \dfrac{1}{26}}[/tex]

The standard error of the mean = [tex]24.45 \times \sqrt{1+0.03846153846}[/tex]

The standard error of the mean = [tex]24.45 \times \sqrt{1.03846153846}[/tex]

The standard error of the mean = [tex]24.45 \times 1.019049331[/tex]

The standard error of the mean = 24.91575614

Recall that : At confidence level of 95% and Degree of freedom df of  25 ;

t-value = 1.7080

∴

The Margin of error = t-value × S.E

The Margin of error = 1.7080 × 24.91575614

The Margin of error = 42.55611149

The upper prediction bound for the escape time of a single additional worker  is calculate by the addition of

Sample Mean + Margin of Error

= 371.08 + 42.55611149

= 413.6361115

[tex]\approx[/tex] 413.64

The upper prediction bound for the escape time of a single additional worker  is 413.64

Answer:

it takes approximately 3 hours

Step-by-step explanation:

Answer:

Step-by-step explanation:

give brainllest please °∩°

Answer:

False

Step-by-step explanation:

A tessellation refest to a shape that is repeated over and over again covering a plane without any gaps or overlaps. The statement is false given that regular tessellations use only one polygon. Semi-regular tessellations are created with more than one type of regular polygon.

Answer:

15 pt

Step-by-step explanation:

to convert qt to pt you multiply by 2 so 7 and 1/2 times 2 is 15

Answer:

The answer is A.

Step-by-step explanation:

In a linear equation, y = mx + b, m is represented as gradient (slope) and b is the y-intercept.

So for this question, m is 2/3 and b is 1.

Answer:

The answer is

Step-by-step explanation:

Surface area of a sphere is given by

S = 4πr²

where r is the radius

From the question r = 11cm

So the surface area of the sphere is

4π(11)²

= 4(121)π

= 484π

= 1520.5308

Which is

1520.5 cm² to the nearest tenth

Hope this helps you

Answer:

f^-1(x) = x + 5

Step-by-step explanation:

f(x) = x-5

y = x-5

Exchange x and y

x = y-5

Solve for y

x+5 = y-5+5

x+5 =y

The inverse is x+5

Answer:

[tex]\boxed{x = 15}[/tex]

Step-by-step explanation:

Let the number be x

Condition:

[tex]2x - \frac{2}{3} x = 20[/tex]

Multiplying 3 to both sides

=> 3(2x) - 2x = 3(20)

=> 6x - 2x = 60

=> 4x = 60

Dividing both sides by 4

=> x = 15

Answer:

15

Step-by-step explanation:

Let x be that number.

2/3 of x subtracted from twice of x is 20.

2x - 2/3x = 20

Solve for x.

Combine like terms.

4/3x = 20

Multiply both sides by 3/4

x = 60/4

x = 15

The number is 15.

Step-by-step explanation:

The formulae to find them are:

and mode= number of greatest frequency.

(note; f is frequency, N is number of data and x is x is the raw data)

hope it helps..

Answer:

26

Step-by-step explanation:

Given that:

At time, t=0, Billy puts 625 into an account paying 6% simple interest

At the end of year 2, George puts 400 into an account paying interest at a force of interest, 1/(6+t), for all t ≥ 2.

If both accounts continue to earn interest indefinitely at the levels given above, the amounts in both accounts will be equal at the end of year n. Calculate n.

In order to calculate n;

Let K constant to be the value of time for both accounts

At  time, t=0, the value of time K when Billy puts 625 into an account paying 6% simple interest is:

[tex]K = 625 \times (1+ 0.06 K)[/tex]

[tex]K = 625 +37.5 K[/tex]

At year end 2; George  amount of 400 will grow at a force interest, then the value of  [tex]K = 400 \times e^{\int\limits^2_k {\dfrac{1}{6+t}} \, dx }[/tex]

[tex]K =400 \times \dfrac{6+K}{6+2}[/tex]

[tex]K =400 \times \dfrac{6+K}{8}[/tex]

[tex]K =50 \times ({6+K})[/tex]

[tex]K =300+50K[/tex]

Therefore:

If K = K

Then:

625 + 37.5 = 300 +50 K

625-300 = 50 K - 37.5 K

325 = 12.5K

K = 325/12.5

K = 26

the amounts in both accounts  at the end of year n = K = 26

Answer:  x = ¹/₂ ± √⁸¹

                     ------------

                            2

Step-by-step explanation:

First write out the equation

x² - x - 20

Now we now write the equation by equating to 0

x² - x - 20 = 0

We now move 20 to the other side of the equation. So

x² - x    =  20,

We now add to both side of the equation square of the half the coefficient of the (x) and not (x²) which is (1) . So, the equation now becomes

x² - x + ( ¹/₂ )² = 20 + ( ¹/₂ )²

x² - ( ¹/₂ )²       = 20 + ¹/₄

( x - ¹/₂ )²       = 20  + ¹/₄, we now resolve the right hand side expression into fraction

( x - ¹/₂ )²          =  ⁸¹/₄ when the LCM is made 4

Taking the square root of both side to remove the square,we now have

x - ¹/₂               =  √⁸¹/₄

x - ¹/₂               =     √⁸¹/₂

Therefore,

                    x = ¹/₂ ± √⁸¹

                          -----------

                               2

Answer

Step-by-step explanation:

Given,

r = 10

Let's create an equation,

[tex]3r = 10 + 5s[/tex]

plugging the value of r

[tex]3 \times 10 = 10 + 5s[/tex]

Multiply the numbers

[tex]30 = 10 + 5s[/tex]

Move 5s to L.H.S and change its sign

Similarly, Move 30 to R.H.S and change its sign.

[tex] - 5s = 10 - 30[/tex]

Calculate

[tex] - 5s = - 20[/tex]

The difference sign ( - ) should be cancelled on both sides

[tex]5s = 20[/tex]

Divide both sides of the equation by 5

[tex] \frac{5s}{2} = \frac{20}{5} [/tex]

Calculate

[tex]s = 4[/tex]

The value of s is 4.

Hope this helps..

Best regards!!

Answer:

A. 4 (on edgenuity)

Step-by-step explanation:

Answer:

500 pounds

Step-by-step explanation:

Let the pressure applied to the leverage bar be represented by p

Let the distance from the object be represented by d.

The pressure applied to a leverage bar varies inversely as the distance from the object.

Written mathematically, we have:

[tex]p \propto \dfrac{1}{d}[/tex]

Introducing the constant of proportionality

[tex]p = \dfrac{k}{d}[/tex]

If 150 pounds is required for a distance of 10 inches from the object

[tex]150 = \dfrac{k}{10}\\\\k=1500[/tex]

Therefore, the relationship between p and d is:

[tex]p = \dfrac{1500}{d}[/tex]

When d=3 Inches

[tex]p = \dfrac{1500}{3}\\\implies p=500$ pounds[/tex]

The pressure applied when the distance is 3 inches is 500 pounds.

Answer:

Number:3.75

Equation:7 x-9=3(x+2)

Step-by-step explanation:

Let the number be x.

According to the question,

7 x-9=3(x+2)

7 x-9= 3 x+ 6

7 x- 3 x= 9+6

4 x= 15

x=15/4

x=3.75

If you verify the answer you will get,

11.25=11.25

Thank you!

Answer:

a = 37

Step-by-step explanation:

the sum of any triangle angles is 180

then 62 + 81 + a = 180

a = 37

.. ..

Answer:

a = 37 degrees

Step-by-step explanation:

81+62 = 143

We know that all angles of a triangle = 180 degrees

180-143= 37 degrees

a = 37 degrees

Answer:

15%

Step-by-step explanation:

To calculate the margin of error, we can adopt this formula

Margin of error = critical value* (standard deviation/sqrt of sample size)

Where critical value is 2.33, sd is 0.78 and sample size is150.

Thus, we have:

Margin of error = 2.33*(0.78/√150)

Margin of error = 2.33*(0.78/12.2474)

Margin of error =2.33*0.06369

Margin of error = 0.1484 which is a 15% margin of error

Answer:

Total cost = $4,873

Therefore, the booking cost of hotel 5 would be $4,873

Step-by-step explanation:

Please refer to the attached table.  

The total cost includes the cost of the room and the cost of buffet dinner.

From the given table hotel 5,

The cost of the room for 120 people is found to be $166 per hour.

The conference will last for 5 hours so the total cost of the room is

Cost of room = 5*$166 = $830

From the given table hotel 5,

The cost of the buffet dinner per head is found to be $30.

Since there are total 120 people so the total cost of dinner is

Cost of dinner = 120*$30 = $3600

Total cost = $830 + $3600 = $4430

We are given that hotel 5 has recently increased the total chargers by 10%

Total cost = $4430*1.10

Total cost = $4,873

Therefore, the booking cost of hotel 5 would be $4,873.

Answer:

A. y ≤ 1/2x + 2

Step-by-step explanation:

Well look at the graph,

It is a solid line with it shaded down,

meaning it is y ≤,

So we can cross out B. and D.

So the y intercept is 2, we know this because the y intercept is the point on the line that touches the y axis.

now the slope can be found by seeing how far away each points are from each other,

Hence, the answer is A. y ≤ 1/2x + 2

The answer is 3,240

Explanation:

To calculate the total income tax, it is necessary to calculate what is the 15% of 8000, and 17% for the remaining money, which is 12.000 (20,000 - 8,000= 12,000). Considering the statement specifies the 15% is paid for the first 8,000 and from this, the 17% is paid. Now to know the percentages you can use a simple rule of three, by considering 8000 and 12000 as the 100%. The process is shown below:

1. Write the values

[tex]8000 = 100[/tex]

[tex]x = 15[/tex] (the percentage you want to know)

2. Use cross multiplication

[tex]x =\frac{8000 x 15 }{100}[/tex]

[tex]x = 1200[/tex]

This means for the first 8000 the money Rafael needs to pay is 1,200

Now, let's repeat the process for the remaining money (12,000)

[tex]12000 = 100\\\\[/tex]

[tex]x = 17[/tex]

[tex]x = \frac{12000 x 17}{100}[/tex]

[tex]x = 2040[/tex]

Finally, add the two values [tex]1200 + 2040 = 3240[/tex]

Answer:

23+15i

Step-by-step explanation:

(-3+2i) (-3-7i)

multiply -3 w (-3+2i) and multiply -7i w (-3+2i)

9-6i+21i-14i^2

combine like terms

9+15i-14i^2

i squared is equal to -1 so

9+15i-(14x-1)

9+14+15i

23+15i

hope this helps :)

<-------------------------------------------------->

   8      9     10     11     12     13     14  (number of hours spent)

                dot plot

Answer:

(A) Draw a number line from 8 to 14. Show the frequency of each number. Title the dot plot.

Step-by-step explanation:

Answer:

[tex] A = 70.6 [/tex] ≈ 71°

[tex] x = 36.5 [/tex]

Step-by-step explanation:

Step 1: Use the Law of sine to find A

[tex] \frac{sin(A)}{38} = \frac{sin(44)}{28} [/tex]

Cross multiply:

[tex] sin(A)*28 = sin(44)*38 [/tex]

[tex] sin(A)*28 = 0.695*38 [/tex]

Divide both sides by 28:

[tex] \frac{sin(A)*28}{28} = \frac{0.695*38}{28} [/tex]

[tex] sin(A) = 0.9432 [/tex]

[tex] A = sin^{-1}(0.9432) [/tex]

[tex] A = 70.6 [/tex]

A ≈ 71°

Step 2: find the measure of the angle opposite side x

Angle opposite side x = 180 - (71+44) (sum of triangle)

= 180 - 115 = 65°

Step 3: find x using the law of sines

[tex] \frac{x}{sin(65)} = \frac{28}{sin(44)} [/tex]

[tex] \frac{x}{0.906} = \frac{28}{0.695} [/tex]

Multiply both sides by 0.906

[tex] x*0.695= 28*0.906 [/tex]

Divide both sides by 0.695

[tex] \frac{x*0.695}{0.695} = \frac{28*0.906}{0.695} [/tex]

[tex] x = \frac{28*0.906}{0.695} [/tex]

[tex] x = 36.5 [/tex]

Answer:

y + 4 = 4/3(x - 6).

Step-by-step explanation:

The point-slope formula is shown below. We just need to find the slope.

(-4 - (-8)) / (6 - 3) = (-4 + 8) / 3 = 4 / 3

m = 4/3, y1 = -4, and x1 = 6.

y - (-4) = 4/3(x - 6)

y + 4 = 4/3(x - 6).

Hope this helps!

Answer:

Largest possible length is 21 inches.

Step-by-step explanation:

Given:

Total material available = 60 inches

Length to be 3 more than twice of width.

To find:

Largest possible length = ?

Solution:

As it is rectangular shaped frame.

Let length = [tex]l[/tex] inches and

Width = [tex]w[/tex] inches

As per given condition:

[tex]l = 2w+3[/tex] ..... (1)

Total frame available = 60 inches.

i.e. it will be the perimeter of the rectangle.

Formula for perimeter of rectangle is given as:

[tex]P = 2 \times (Width + Length)[/tex]

Putting the given values and conditions as per equation (1):

[tex]60 = 2 \times (w+ l)\\\Rightarrow 60 = 2 \times (w+ 2w+3)\\\Rightarrow 60 = 2 \times (3w+3)\\\Rightarrow 30 = 3w+3\\\Rightarrow 3w = 27\\\Rightarrow w = 9 \ inch[/tex]

Putting in equation (1):

[tex]l = 2\times 9+3\\\Rightarrow l = 21\ inch[/tex]

So, the answer is:

Largest possible length is 21 inches.

Answer:

20.8 hours

Step-by-step explanation:

2 3/5 = 2.6.The painter will take (2.6 × 8) = 20.8 hours to paint a wall.

Hope this helps and pls mark as brianliest :)

Answer:

20.8, 20 4/5, and 104/5

Answer:

The answer is

Step-by-step explanation:

x² + 2x - 3 - 2x² + x + 4

Group like terms

That's

x² - 2x² + 2x + x - 3 + 4

Simplify

- x² + 3x + 1

when x = 3

We have

(-3)² + 3(3) + 1

9 + 9 + 1

18 + 1

19

Hope this helps you

Answer:

D) 53 Degrees.

Step-by-step explanation:

Things we need to establish beforehand: We know that Lines OZ and OX are equal because they are both radii of the circle. We can make an Iscoceles traingle by drawing a line between ZX. We know angle YZO and angle YXO is a right angle because YZ and XY are tangent to the circle. The Arc angle is the same angle as angle ZOX.

1) Find angles OZX and OXZ. these will be 26.5, because 180-127 is 53, which is the sum of the two angles. the two angles are the same, so divide 53 by 2.

2) Find Angles XZY and ZXY. We know that YZO is a right angle, and both XZY and OZX make up this right angle so XZY + OZX = 90. OZX is 26.5, so 90-26.5=XZY. XZY = ZXY, so both angles equal 63.5.

3) Now that we have two angles of triangle XYZ, we can find angle XYZ.     180-(XZY+ZXY)=XYZ, so (180-(63.5+63.5)=53. Angle XYZ=53.