Explain why it isn’t always best to solve a system of equations by graphing. Give an example in which this is the case.

Answer:

96 ft^2

Step-by-step explanation:

volume=l^3

l=4

4x4x4=64

Surface area (4x4)=16

16x6=96

Answer:

SA =96 ft^2

Step-by-step explanation:

The volume of a cube is given by

V = s^3

64 = s^3

Take the cube root of each side

64 ^ 1/3 = s^3 ^ 1/3

4 =s

The side length si 4

The surface area of a cube is

SA = 6 s^2

SA = 6 * 4^2

SA = 6 * 16

SA =96 ft^2

Answer:

The required sample size 'n' = 97 .41 hours

Step-by-step explanation:

Explanation:-

Given standard deviation of the Population 'σ' = 3 hours

Given the Margin of error = [tex]\frac{1}{2} hour[/tex]

The Margin of error is determined by

[tex]M.E = \frac{Z_{\frac{\alpha }{2} S.D} }{\sqrt{n} }[/tex]

Given level of significance ∝ = 0.10 or 0.90

Z₀.₁₀ = 1.645

[tex]\frac{1}{2} =\frac{1.645 X 3}{\sqrt{n} }[/tex]

Cross multiplication , we get

[tex]\sqrt{n} = 2 X 1.645 X 3[/tex]

√n =  9.87

Squaring on both sides, we get

n = 97.41 hours

Final answer:-

The required sample size 'n' = 97.41 hours

Answer:

The probability that, in any hour, exactly 5 cars will enter the car wash is P(x=5)=0.0920.

Step-by-step explanation:

This can be modeled as a Poisson random variable.

The mean rate is the parameter of the Poisson distribution:

[tex]\lambda=4\;\text{cars/half an hour}=8\;\text{cars/hour}[/tex]

The probability that exactly k cars will enter the car wash can be calculated as:

[tex]P(x=k)=8^{k} \cdot e^{-8}/k![/tex]

Then, the probability that exactly 5 cars will enter the car wash is:

[tex]P(5)=8^{5} \cdot e^{-8}/5!=32768*0.0003/120=0.0920\\\\[/tex]

The probability that, in an hour, exactly 5 cars will enter the car wash will be 0.0920.

Probability means possibility. It deals with the occurrence of a random event. The value of probability can only be from 0 to 1.

Its basic meaning is something is likely to happen. It is the ratio of the favorable event to the total number of events.

The mean rate is found as;

[tex]\rm \lambda =4 \ cars / half \ an \ hour = 8 car / hour[/tex]

The probability that exactly k cars will enter the car wash

[tex]P(x=K) = \frac{8^k e^{-8}}{k\!}\\\\P(x=5) = \frac{8^5 e^{-8}}{5\!}\\\\ P(x=5)=0.0920[/tex]

Hence the probability that, in an hour, exactly 5 cars will enter the car wash will be 0.0920.

To learn more about the probability link is given below.

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Answer:

please see the attached picture for full solution...

Hope it helps...

Good luck on your assignment....

Answer:

0| 2

1| 2

2| 0 0 3 9

3| 2 4 4 4 8 8

4| 2 2 4 5 5 6 7

Step-by-step explanation:

Same as the other similar questions

hope this helps!

Answer:

The answer is the last one because if the diagonals of a quadrilateral bisect each other then it's a parallelogram.

Answer:

Last answer choice

Step-by-step explanation:

One of the prerequisites for a quadrilateral to be a parallelogram is for the diagonals to bisect each other. Since K is the midpoint, this means that it is halfway between the ends of each of the diagonals, and that they therefore bisect each other. Hope this helps!

Answer:

0.48% probability that all four are new

Step-by-step explanation:

The homes are chosen "without replacement", which means that after a home is visited, it is not elegible to be visited again. So we use the hypergeometric distribution to solve this question.

Hypergeometric distribution:

The probability of x sucesses is given by the following formula:

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]

In which:

x is the number of sucesses.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

In this question:

Total of 10 homes, so N = 10.

We want 4 new, so x = 4.

In total, there are 4 new, so k = 4.

Sample of four homes, so n = 4.

Then

[tex]P(X = 4) = h(4,10,4,4) = \frac{C_{4,4}*C_{6,0}}{C_{10,4}} = 0.0048[/tex]

0.48% probability that all four are new

The calculated probability is "0.0048".

From a total of [tex]N=10\ \ \text{homes},\ r=4[/tex] are completely new while 6 are not.

Let X indicate the series of innovative dwellings in a sample of[tex]n=4[/tex] homes.

X is the next step. Algebraic distribution for parameters[tex]N=10, r=4, \ \ and\ \ n = 4[/tex] Only integer values in this range: can be given to a hypergeometric random variable.

[tex]\to [ \max {(0,\,n+r-N)}, \min {(n,\,r)} ] = [ 0, 4 ] \\\\ \to P( X = 4) \\\\ \to N=10\\\\ \to r=4\\\\ \to n = 4[/tex]

[tex]\to \bold{P(X=k) = \dfrac{\binom{r }{ k}{\binom{N-r} {n-k}}}{\binom{N}{n}}} \\\\\to P(X =4 ) = \dfrac{\binom{r }{ 4}{\binom{N-r} {n-4}}}{\binom{N}{n}} \\\\[/tex]

                   [tex]= \dfrac{\binom{4 }{ 4}{\binom{10-4} {4-4}}}{\binom{10}{4}}\\\\= \dfrac{\binom{4 }{ 4}{\binom{6} {0}}}{\binom{10}{4}} \\\\= \dfrac{ 1 \times 1}{210} \\\\= \dfrac{ 1}{210} \\\\= \dfrac{1}{210} \\\\= 0.004762[/tex]

Using the excel function:

[tex]\text{HYPGEOM.DIST( k, n, r, N. cumulative)}[/tex]  for calculating the [tex]P_{X} (4)[/tex]:

[tex]\to \text{HYPGEOM.DIST( 4, 4, 4, 10, FALSE) = 0.0047619047619}[/tex]

[tex]\to P(X= 4 ) = \frac{1}{210} = { 0.0048 }[/tex]

Find out more information about the probability here:

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Answer:

x^2

Step-by-step explanation:

[tex]x^4\cdot x^{-2}= \\\\x^{4-2}= \\\\x^2[/tex]

Hope this helps!

Answer:

[tex]x^{2}[/tex]

Step-by-step explanation:

[tex]x^4 \times x^{-2}[/tex]

[tex]x^{4+-2}[/tex]

[tex]x^{4-2}[/tex]

[tex]x^{2}[/tex]

Answer:

As the P-value is very low, we can conclude that there is enough evidence to support the claim that the survival rate is significantly higher when the seatbelt is used.

Step-by-step explanation:

We have a hypothesis test that compares the survival rate using the seatbelt versus the survival rate not using it.

The claim is that the survival rate (proportion) is significantly higher when the seatbelt is used.

Then, the null hypothesis is that the seatbelts have no effect (both survival rates are not significantly different).

The P-value is the probabilty of the sample we have, given that the null hypothesis is true. In this case, this value is 0.0001.

This is very low, what gives enough evidence to claim that the survival rate is significantly higher when the seatbelt is used.

Answer:

C. with 3000 successes of 5000 cases sample

Step-by-step explanation:

Given that we need to test if the proportion of success is greater than 0.5.

From the given options, we can see that they all have the same proportion which equals to;

Proportion p = 30/50 = 600/1000 = 0.6

p = 0.6

But we can notice that the number of samples in each case is different.

Test statistic z score can be calculated with the formula below;

z = (p^−po)/√{po(1−po)/n}

Where,

z= Test statistics

n = Sample size

po = Null hypothesized value

p^ = Observed proportion

Since all other variables are the same for all the cases except sample size, from the formula for the test statistics we can see that the higher the value of sample size (n) the higher the test statistics (z) and the highest z gives the strongest evidence for the alternative hypothesis. So the option with the highest sample size gives the strongest evidence for the alternative hypothesis.

Therefore, option C with sample size 5000 and proportion 0.6 has the highest sample size. Hence, option C gives the strongest evidence for the alternative hypothesis

Step-by-step explanation:

Joe mama

Answer:

Pillows:

Blankets:

Pet Beds:

Step-by-step explanation:

18 + 45 + 27 = 90 (there are 90 students)

18 out of 90 = 20%

45 out of 90 = 50%

27 out of 90 = 30%

Hope this helps!

Answer:

[tex]n=\frac{0.04(1-0.04)}{(\frac{0.03}{1.64})^2}=114.76[/tex]  

And rounded up we have that n=115

Step-by-step explanation:

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by [tex]\alpha=1-0.90=0.1[/tex] and [tex]\alpha/2 =0.05[/tex]. And the critical value would be given by:

[tex]z_{\alpha/2}=-1.64, z_{1-\alpha/2}=1.64[/tex]

Solution to the problem

The margin of error for the proportion interval is given by this formula:  

[tex] ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}[/tex]    (a)  

The proportion of defectives is estimated as: [tex]\hat p=0.04[/tex]. And on this case we have that the margin of error is [tex]ME =\pm 0.03[/tex] and we are interested in order to find the value of n, if we solve n from equation (a) we got:  

[tex]n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}[/tex]   (b)  

And replacing into equation (b) the values from part a we got:

[tex]n=\frac{0.04(1-0.04)}{(\frac{0.03}{1.64})^2}=114.76[/tex]  

And rounded up we have that n=115

Answer:

7 donkeys

Step-by-step explanation:

Given

A system consisting of donkeys and tourists

Heads = 50

Legs = 114

Required

Calculate number of donkeys.

Represent donkeys with D and tourists with T.

By means of identification; donkeys and tourists (human) both have 1 head.

This implies that

Number of Heads = D + T

50 = D + T ----- Equation 1

While each donkey have 4 legs, each tourists have 2 legs.

This implies that

Number of legs = 4D + 2T

114 = 4D + 2T ---- Multiply both sides by ½

114 * ½ = (4D + 2T) * ½

57 = 4D * ½ + 2T * ½

57 = 2D + T ----- Equation 2

Subtract equation 1 from 2

57 = 2D + T

- (50 = D + T)

---------------------

57 - 50 = 2D - D + T - T

7 = D

Recall that D represents the number of donkeys.

So, D = 7 implies that

The total number of donkeys are 7

Answer:

i). 10 levels of the bricks

ii). 320 bricks

Step-by-step explanation:

First level contains number of bricks = 50

Second level will contain = 50 - 4 = 46 bricks

Similarly, 3rd level will contain number of bricks = 46 - 4 = 42

Therefore, sequence formed for the number of bricks in each level of the wall will be,

50, 46, 42........14

This sequence is an arithmetic sequence having,

First term 'a' = 50

Common difference 'd' = 46 - 50 = (-4)

Last term of the sequence [tex]T_{n}[/tex]= 14

i). Expression representing last term will be,

  [tex]T_{n}=a+(n-1)d[/tex]

  Here [tex]T_{n}[/tex] = nth term

  a = first term

  n = number of term (Number of level of the wall)

  d = common difference

  By substituting these values in the formula,

  14 = 50 + (n - 1)(-4)

  14 - 50 = (-4)(n - 1)

  -36 = -4(n - 1)

  9 = (n - 1)  

  n = 9 + 1

  n = 10

ii). Number of bricks used in the wall = Sum of the sequence

   Expression for the sum of an arithmetic sequence is,

   [tex]S_n=\frac{n}{2}[2a+(n-1)d][/tex]

   [tex]S_n=\frac{10}{2}[2\times 50+(10-1)(-4)][/tex]

        = 5(100 - 36)

        = 320 bricks

Answer:

  A) 10, -3.73, -6.035, -6.259 . . . cm/s

  B) -6.2832 cm/s

Step-by-step explanation:

A) For problems like this, where repeated evaluation of a function is required, I find a graphing calculator or spreadsheet to be an appropriate tool. The attached shows that we defined the position function ...

  p(t) = 2sin(πt) +5cos(πt)

and a function for computing the average velocity from t=1. For some time interval ending at t2, the average velocity is ...

  Va(t2) = Δp/Δt = (p(t2) -p(1))/(t2 -1)

Then, for example, for t2 = 2, the average velocity on the interval [1, 2] is ...

  Va(2) = (p(2) -p(1))/(2 -1) = ((2sin(2π) +5cos(2π)) -(2sin(π) +5cos(π)))/(1)

  = (2·0+5·1 -(2·0 +5·(-1)) = 10 . . . . matches the table value for x1 = 2.

Then the average velocity values for the intervals of interest are ...

  1) [1, 2]   Va = 10

  2) [1, 1.1]   Va = -3.73

  3) [1, 1.01]   Va = -6.035

  4) [1, 1.001]   Va = -6.259

__

B) Sometimes a better estimate is obtained when the interval is centered on the point of interest. Here, we can compute the average velocity on the interval [0.999, 1.001] as a better approximation of the instantaneous velocity at t=1. That value is ...

  [0.999, 1.001]   Va = -6.283175*

Our estimate of V(1) is -6.2832 cm/s.

The exact value is -2π ≈ -6.2831853... cm/s

__

* This is the average of the Va(0.999) and Va(1.001) values in the table.

Let's think:

1 ton ------------ 1000 kilograms

3.2 tons ----------- x kilograms

Multiply in cross

1 . x = 1000 . 3.2

x = 3200

So 3.2t = 3200 kilograms

Answer:

It is 2902.99 to be exact

Step-by-step explanation:

Answer:

Step-by-step explanation:

Given the equation j – 16 = 7, If Nolan is using substitution to determine if 23 is a solution to the equation, then Nolan need to make j the subject of the formula from the equation. The following statements must therefore be made by Nolan.

First, Nolan must substitute for the value of j in the equation.

To simplify, Nolan must subtract the value of  7 from both sides to have;

j – 16 - 7= 7 - 7

j – 23 = 0

Then Nolan must add 23 to both sides of the equation to get the value of j as shown;

j – 23 + 23 = 0+23

j = 23

23 is therefore a solution to the equation

Answer:First, Nolan must substitute 23 for j.To simplify, Nolan must subtract 16 from 23. 23 is a solution of the equation.

Step-by-step explanation:

I got it right on Edge

Answer:

[tex]y = (e^{4x}{4} + kx+d) \cdot c_1e^{-3x} =  \frac{e^{x}}{4} + Ae^{-3x}+Bxe^{-3x}[/tex] where A,B are constants.

Step-by-step explanation:

Consider the differential equation [tex]y''+6y'+9y = 4e^{x}[/tex]. To find the homogeneus solution, we assume that [tex]y = Ae^{rt}[/tex] and replace it in the equation [tex]y''+6y'+9y = 0[/tex]. If we do so, after using some properties of derivatives and the properties of the exponential function we end up with the equation

[tex]r^2+6r+9 = 0 = (r+3)^2[/tex]

which leads to r = -3. So, one solution of the homogeneus equation is [tex]y_h = c_1e^{-3x}[/tex], where c_1 is a constant.

To use the order reduction method, assume

[tex] y = v(x)y_h(x)[/tex]

where v(x) is an appropiate function. Using this, we get

[tex]y'= v'y+y'v[/tex]

[tex]y''=v''y+y'v'+y''v+v'y'=v''y+2v'y'+y''v[/tex]

Plugging this in the original equation we get

[tex]v''y+2v'y'+y''v + 6(v'y+y'v) +9vy=4e^{x}[/tex]

re arranging the left side we get

[tex]v''y+2v'y'+6v'y+v(y''+6y'+9y)=4e^{x}[/tex]

Since y is a solution of the homogeneus equation, we get that [tex]y''+6y'+9y=0[/tex]. Then we get the equation

[tex]yv''+(2y'+6y)v' = 4e^{x}[/tex]

We can change the variable as w = v' and w' = v'', and replacing y with y_h, we get that the final equation to be solved is

[tex] e^{-3x}w'+(6e^{-3x}-6e^{-3x})w =4e^{x}[/tex]

Or equivalently

[tex]w' = 4e^{4x}[/tex]

By integration on both sides, we get that w = e^{4x}+ k[/tex] where k is a constant.

So by integration we get that v = [tex]e^{4x}{4} + kx+d[/tex] where d is another constant.

Then, the final solution is

[tex]y = (e^{4x}{4} + kx+d) \cdot c_1e^{-3x} =  \frac{e^{x}}{4} + Ae^{-3x}+Bxe^{-3x}[/tex] where A,B are constants

Answer:

a. They are empty set.

b. they are finite set.

Solution,

a. A={ prime number between 6 and 7}

There are not any number between 6 and 7.

So there will be no Elements.

A={ }

It is empty set.

Empty set are those set which doesn't contain any Element.

b.B={multiples of 2 less than 20}

B={2,4,6,8,10,12,14,16,18}

It is a finite set.

Finite set are those set which we can count easily.

Hope this helps...

Good luck on your assignment...

Answer:

a) Mean number of beans = 33.4 per coco pad

b) Standard deviation of the  beans = 5.2   per coco pad

Step-by-step explanation:

Step(i):-

a)

Given data  30, 28, 30, 35, 40, 25, 32, 36, 38 and 40.

mean of beans

  x⁻ = ∑x/n

[tex]x^{-} = \frac{30+ 28+30+35+40+25+32+36+38 + 40.}{10} = 33.4[/tex]

Mean number of beans per coco pad  = 33.4

step(ii):-

b)

standard deviation

∑(xi - x⁻)²  =  (30-33.4)²+ (28-33.4)²+(30-33.4)²+(35-33.4)²+(40-33.4)²+(25-33.4)²+(32-33.4)²+(36-33.4)²+ (38-33.4)²+(40-33.4)²

On calculation , we get

      ∑(xi - x⁻)²  = 242.4

standard deviation

 =        [tex]\sqrt{\frac{sum((x-x^{-} )^{2} }{n-1} } = \sqrt{\frac{242.4}{10-1} } = 5.189[/tex]

Standard deviation of the  beans  (σ) = 5.2   per coco pad

If we spin the spinner 11 times, 4 is the best prediction possible for the number of times it will land on pink.

To calculate the expected value of a random variable, simply multiply it with the respective probability and sum the respective products.

Given, total number of outcomes=11.

Total number of pink colored spin= 4

Probability of a spin resulting pink color=4/11

Expected number of spins of pink color= [tex]\sum xp(x)[/tex]

=(1×4/11)+(2×4/11)+(3×4/11)+(4×4/11)

=4/11(1+2+3+4)

=40/11

=3.63 ≈ 4

Thus, the best prediction possible for the number of times it will land on pink is 4.

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Incomplete:

Image of spinner is missing in the question, Therefore attaching it below:

Answer:

  appropriately writing the proportion can reduce or eliminate steps required to solve it

Step-by-step explanation:

The proportion ...

  [tex]\dfrac{A}{B}=\dfrac{C}{D}[/tex]

is equivalent to the equation obtained by "cross-multiplying:"

  AD = BC

This equation can be written as proportions in 3 other ways:

  [tex]\dfrac{B}{A}=\dfrac{D}{C}\qquad\dfrac{A}{C}=\dfrac{B}{D}\qquad\dfrac{C}{A}=\dfrac{D}{B}[/tex]

  Effectively, the proportion can be written upside-down and sideways, as long as the corresponding parts are kept in the same order.

I find this most useful to ...

  a) put the unknown quantity in the numerator

  b) give that unknown quantity a denominator of 1, if possible.

__

The usual method recommended for solving proportions is to form the cross-product, as above, then divide by the coefficient of the variable. If the variable is already in the numerator, you can simply multiply the proportion by its denominator.

Example:

  x/4 = 3/2

Usual method:

  2x = 4·3

  x = 12/2 = 6

Multiplying by the denominator:

  x = 4(3/2) = 12/2 = 6 . . . . . . saves the "cross product" step

__

Example 2:

  x/4 = 1/2 . . . . we note that "1" is "sideways" from x, so we can rewrite the proportion as ...

  x/1 = 4/2 . . . . . . written with 1 in the denominator

  x = 2 . . . . simplify

Of course, this is the same answer you would get by multiplying by the denominator, 4.

The point here is that if you have a choice when you write the initial proportion, you can make the choice to write it with x in the numerator and 1 in the denominator.

Answer:

[tex]\boxed{\sf \ \ age = 10\ \ }[/tex]

Step-by-step explanation:

Hello,

let's write the mean computation, we note x the age of the additional person

[tex]\dfrac{14+14+18+18+22+x}{6}=16[/tex]

[tex]<=> 14+14+18+18+22+x = 6*16=96\\\\<=> x = 96 - ( 14+14+18+18+22)= 10[/tex]

So the age of the person is 10

hope this helps

Answer:

10

Step-by-step explanation:

The mean is the sum of terms divided by number of terms.

Let x be the age of the person who entered the room.

(14+14+18+18+22+x)/6 = 16

(x + 86)/6 = 16

x + 86 = 96

x = 10

The age of the person who entered the room is 10.

Answer:

y= -5x +7

Step-by-step explanation:

We can see points on the graph:

The function in general form is:

Let's find the slope and y-intercept as per identified points on the graph:

b= y- mx

Based on the found values of m and b, the given line is:

Answer:

The answer is C: y + 8 = -5(x - 3)

Step-by-step explanation:

I took the assignment on Edge

Answer:

We want a line that passes through the point (4, 7/2)

and we have no other information of this line, so we can not fully find it, but we can find a general line.

We know that a line can be written as:

y = a*x + b.

Now we want that, when x = 4, we must have y = 7/2.

7/2 = a*4 + b

b = -a*4 + 7/2

Then we can write this line as:

y = a*x - a*4 + 7/2.

Where a can take any value, and it is the slope of our line.

Answer:

A

Step-by-step explanation:

Answer:

$37.50

Step-by-step explanation:

50*.25=12.50

Take $50 - 12.50  = 37.50

Answer: B, 1 mile / 5280 ft.

Step-by-step explanation: If you need to convert feet to miles the unit multiplier (ratio) that you use should have miles on top and feet on the bottom so that the feet cancel when you multiply, leaving miles as the unit. B is the only answer that has miles on top and feet on the bottom as well as the correct amounts (1 mile and 5280 ft).

Answer:

solution,

[tex]5x + 8 - 3x = - 10 \\ or \: 5x - 3x + 8 = -10 \\ or \: 2x + 8 = -10 \\ or \: 2x = -10 - 8 \\ or \: 2x = -18\\ or \: x = \frac{-18}{2 } \\ x = -9[/tex]

hope this helps..

Good luck on your assignment

Answer:

x = -9

Step-by-step explanation:

5x + 8 - 3x = -10

Rearrange.

5x - 3x + 8 = -10

Subtract like terms.

2x + 8 = -10

Subtract 8 on both sides.

2x = -10 - 8

2x = -18

Divide 2 into both sides.

x = -18/2

x = -9