Factor the expression, and use the factors to find the x-intercepts of the quadratic relationship it represents. Type the correct answer each box, starting with the intercept with the lower value The x- intercepts occur where x = and x =

a) Let A denote the event that 4 candies taken have different tastes, B denote the event that 2 candies have the same taste, and C denote the event that 6 candies include 2 candies with marzipan, 2 candies with nuts and 2 candies with caramel.

b) The probability of event A is 1/210

The probability of event B is 5/126

The probability of event C is 3/70

To find the probability of event A, we need to count the number of ways to choose 4 candies out of 10, where each candy has a different taste. Thus, the probability of event A is given by:

To find the probability of event B, we need to count the number of ways to choose 2 candies of the same taste and 2 candies of different tastes out of 10. There are 4 choices for the taste of the 2 candies that are the same, and 6 choices for the taste of the other 2 candies. Thus, the probability of event B is given by:

To find the probability of event C, we need to count the number of ways to choose 2 candies with marzipan, 2 candies with nuts, and 2 candies with caramel out of 10. There are (3 choose 2) = 3 ways to choose 2 candies with marzipan, (2 choose 2) = 1 way to choose 2 candies with nuts, and (4 choose 2) = 6 ways to choose 2 candies with caramel. Thus, the probability of event C is given by:

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The surface area of a surface parametrized by a function f(s, t), we use the formula:

Surface Area = ∫∫ √[f_s(s,t)^2 + f_t(s,t)^2 + 1] ds dt

The formula above calculates the surface area by integrating the square root of the sum of the squares of the partial derivatives of f with respect to s and t, plus one, over the surface.

Essentially, the formula is finding the magnitude of the gradient of the surface, which gives the rate of change of the surface in all directions.

Surface Area = ∫∫ √[f_s(s,t)^2 + f_t(s,t)^2 + 1] ds dt

The surface area formula can be used to find the surface area of various types of surfaces, such as parametric surfaces, implicit surfaces, and surfaces of revolution.

However, the integration required to evaluate the formula can be quite challenging, especially for complex surfaces. In such cases, numerical methods may be used to approximate the surface area.

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The 90% confidence interval for the average fee for checking a single bag is $21.71 to $28.29, which corresponds to option B) $25 + $3.29

To calculate a 90% confidence interval for the average fee for checking a single bag.

To calculate a 90% confidence interval, we need the sample mean (X), the standard deviation (σ), and the sample size (n). From your question, we have:

X = $25
σ = $6
n = 9

Since we know the standard deviation, we can use the z-score for a 90% confidence interval, which is 1.645 (you can find this in a standard z-table).

Next, we need to calculate the standard error (SE), which is the standard deviation divided by the square root of the sample size:

[tex]SE=\frac{σ}{\sqrt{n} }[/tex]
[tex]SE=  \frac{ 6}{\sqrt{9} }[/tex]
[tex]SE=  \frac{ 6}{3 }[/tex]
SE = $2

Now, multiply the z-score by the standard error:

Margin of Error (ME) = 1.645 × SE
ME = 1.645 × $2
ME = $3.29

Finally, construct the 90% confidence interval by adding and subtracting the margin of error from the sample mean:

Lower Limit: X - ME = $25 - $3.29 = $21.71
Upper Limit: X + ME = $25 + $3.29 = $28.29

Thus, the 90% confidence interval for the average fee for checking a single bag is $21.71 to $28.29, which corresponds to option B) $25 + $3.29.

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28°49€  arc unit into time is approximately 1.867 hours.

We'll convert the given angles from degrees, minutes, and seconds (or cents and euros as placeholders) to degrees in decimal form. Then, we'll convert the angle from arc units to time units.

a) 39°50¢
To convert 50¢ to degrees, divide by 60 (since 1 degree = 60 minutes):
50¢ / 60 = 0.8333 (rounded to four decimal places)

So, 39°50¢ in decimal form is:
39 + 0.8333 = 39.8333°

b) 42°35¢
To convert 35¢ to degrees:
35¢ / 60 = 0.5833 (rounded to four decimal places)

So, 42°35¢ in decimal form is:
42 + 0.5833 = 42.5833°

c) 15°20€
To convert 20€ to degrees (1 degree = 3600 seconds):
20€ / 3600 = 0.0056 (rounded to four decimal places)

So, 15°20€ in decimal form is:
15 + 0.0056 = 15.0056°

d) 1°59€
To convert 59€ to degrees:
59€ / 3600 = 0.0164 (rounded to four decimal places)

So, 1°59€ in decimal form is:
1 + 0.0164 = 1.0164°

Now, we'll convert 28°49€ from arc units to time units:
28°49€ = 28 + (49 / 3600) = 28.0136° (in decimal form)

To convert degrees to time units, multiply by 24 (since there are 24 hours in a day) and divide by 360 (since there are 360 degrees in a circle):

28.0136° * (24 / 360) = 1.867 (rounded to three decimal places)

So, 28°49€ in time units is approximately 1.867 hours.

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Answer:

x = -6

Step-by-step explanation:

you have given

10x + 8y = 12 and 4x + y = -15

so you must put the one var. x or y by same cofficent and in opposite sighn

so 10x + 8y = 12

- 8 (4x + y = -15 ) ......... i multiplied by -8

10x + 8y = 12

-32x - 8y = 120

then you will add the equation

(10x + 8y) + (-32x - 8y) = 12 + 120

afeter you simlify it u will get

-22x = 132

-22x = 132

x = -6 .... by dividing both sides by -22

Answer:

(-6,9)

Step-by-step explanation:

Multiply 4x + y = -15 all the say through by -8 and then add to 10x + 8y = 12

-32x -8y =  120

10x + 8y = 12

-22x =  132  Divide both sides by -22

x = -6

Substitute -6 for x

4x + y = -15

4(-6) + y = -15

-24 + y = -15  Add 24 to both sides

y = 9

Check

10x + 8y = 12

10(-6) + 8(9) = 12

-60 + 72 = 12

12 = 12  checks

4x + y = -15

4(-6) + 9 = -15

-24 + 9 = -15

-15 = -15 Checks.

Helping in the name of Jesus.

Answer:

The mass of the car rounded to the nearest kilogram is 1990 kg, which has an error interval of 1989.5 kg ≤ car mass < 1990.5 kg.

The mass of the person rounded to 1 decimal place is 58.7 kg, which has an error interval of 58.65 kg ≤ person mass < 58.75 kg.

To find the error interval for the combined mass, we need to add the lower and upper bounds of the two intervals:

1989.5 kg + 58.65 kg = 2048.15 kg

1990.5 kg + 58.75 kg = 2049.25 kg

Therefore, the error interval for the combined mass, m, of the car and the person is: 2048.15 kg ≤ m < 2049.25 kg

Answer:

To find the error interval for the combined mass of the car and the person, we need to consider the possible maximum and minimum values for the masses.

For the car, since it is rounded to the nearest kilogram, the actual mass could be anywhere between 1989.5 kg and 1990.5 kg.

For the person, since it is rounded to 1 decimal place, the actual mass could be anywhere between 58.65 kg and 58.75 kg.

To find the maximum and minimum combined masses, we add the maximum possible mass of the car (1990.5 kg) to the maximum possible mass of the person (58.75 kg) and we add the minimum possible mass of the car (1989.5 kg) to the minimum possible mass of the person (58.65 kg):

Maximum combined mass = 1990.5 kg + 58.75 kg = 2049.25 kg

Minimum combined mass = 1989.5 kg + 58.65 kg = 2048.15 kg

Therefore, the error interval for the combined mass, m, of the car and the person is:

2048.15 kg ≤ m < 2049.25 kg

PART A: The component form of vector is: u = <4, 8> and v = <4, 7>

PART B: u + v = <8, 15>

PART C: 5u - 2v = <12, 26>

The component form of a vector is <x, y>.

PART A:

Looking at the graph, vector u is the displacement from (2, -6) to (6, 2). Thus,

u = (6, 2) - (2, -6)

u = (6-2, 2-(-6))

u = (4, 8)

In component form, u = <4, 8>

Vector v is the displacement from (7, 8) to (11, 1). Thus,

v = (11, 1) - (7, 8)

v = (11-7, 8-1)

v = (4, 7)

In component form, v = <4, 7>

PART B:

u + v = <4, 8> + <4, 7>

u + v = <4+4, 8+7>

u + v = <8, 15>

PART C:

5u - 2v = 5*<4, 8> - 2*<4, 7>

5u - 2v = <20, 40> - <8, 14>

5u - 2v = <20-8, 40-14>

5u - 2v = <12, 26>

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The  area of the lateral face of cylinder = 150.79 ft²

The  area of the two bases of the cylinder = 56.55 ft²

The total surface area of the cylinder =  207.34  ft²

We know that the formula for the surface area of cylinder is:

A = 2πrh + 2πr²

where r is the radius of the cylinder

and h is the height of the cylinder

Here, r = 3 ft and h = 8 ft

The area of the lateral face of cylinder would be,

A₁ = 2 × π × r × h

A₁ = 2 × π × 3 × 8

A₁ = 48 × π

A₁ = 150.79 sq. ft.

And the area of two bases is,

A₂ = 2πr²

A₂ = 2 × π × 3²

A₂ = 18 × π

A₂ = 56.55 sq. ft.

The total surface area of cylinder would be,

A = A₁ + A₂

A = 150.79 + 56.55

A = 207.34 sq. ft.

Therefore, the required surface area of cylinder = 207.34 ft²

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The number of frames that the welders would be able to complete in 4 hours would be 10 frames.

The time taken by one welder is 8 hours for one frame which means the work rate would be:

= 1 / 8

= 1 / 8 frames per hour

If we have 20 welders therefore, the work rate per hour would be :

= 1 / 8 x 20

= 2. 5 frames per hour

Given 4 hours, the number of frames they would make is:

= 2. 5 x 4 hours

= 10 frames

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First part of question is:

A welding company produces burglar frames for windows and doors. In order to complete one frame, one welder needs 8 hours.

The answer is: True. When matrix A is upper triangular, its eigenvalues are located on its main diagonal. If you find the eigenvectors corresponding to each eigenvalue, you can construct an eigenvector matrix S.

An upper triangular matrix is a square matrix in which all entries below the main diagonal are zero. An eigenvector of a matrix A is a nonzero vector x such that Ax is a scalar multiple of x. That is, there exists a scalar λ such that Ax = λx.
For a complete upper triangular matrix, all of its eigenvalues are on the diagonal. To see this, consider the characteristic polynomial of a complete upper triangular matrix:
p(λ) = det(A - λI)
where I is the identity matrix. Since A is upper triangular, its determinant is the product of its diagonal entries, and det(A - λI) is a polynomial of degree n (the size of the matrix) in λ. Therefore, there are n roots of p(λ), which correspond to the eigenvalues of A. Since A is completely upper triangular, all of its eigenvalues are on the diagonal.

Now, let's consider the eigenvector matrix S of A. This is a matrix whose columns are the eigenvectors of A. Since A is upper triangular, any eigenvector of A must also be upper triangular (or zero). Therefore, the eigenvector matrix S must also be upper triangular. In summary, if a is a complete upper triangular matrix, then all of its eigenvalues are on the diagonal, and its eigenvector matrix S is upper triangular. Therefore, the statement is true.
"If A is a complete upper triangular matrix, then it has an upper triangular eigenvector matrix S." When a matrix A is upper triangular, its eigenvalues are located on its main diagonal. If you find the eigenvectors corresponding to each eigenvalue, you can construct an eigenvector matrix S. Since A is upper triangular, the eigenvector matrix S will also be upper triangular.

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The numbers that are arranged from greatest to least are

Let's first rewrite the given options in a clearer way and compare the numbers:

A) 1.6 x 10^0; 1.62 x 10^1; 1.7 x 10^(-1)

B) 1.62 x 10^4; 1.6 x 10^1; 1.7 x 10^1

C) 1.6 x 10^0; 1.7 x 10^0; 1.62 x 10^4

D) 1.62 x 10^0; 1.7 x 10^0; 1.6 x 10^1

Simplifying the numbers

Option A:

1.6 x 10^0 = 1.6; 1.62 x 10^1 = 16.2; 1.7 x 10^(-1) = 0.17

not in descending order

Option B:

1.62 x 10^4 = 16200; 1.6 x 10^1 = 16; 1.7 x 10^1 = 17

in descending order

Option C:

1.6 x 10^0 = 1.6; 1.7 x 10^0 = 1.7; 1.62 x 10^4 = 16200

in descending order

Option D:

1.62 x 10^0 = 1.62; 1.7 x 10^0 = 1.7; 1.6 x 10^1 = 16

not in descending order

Hence we can say that options B and C correctly sorted numbers from highest to lowest as follows:

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Answer:

z = 10

Step-by-step explanation:

Lets explain this to you,

Step one: Solve with the parenthesis first (2 times z is 2z and 2 times -8.5 is

-17)

Step two: Subtract 2z from both sides (0.3z - 2z = - 1.7) (2z - 2z = 0)

Step three: Divide negative 1.7 on both sides (-1.7 = -17)

Step four: Simplify - 1.7 / 17 which will finally be 10

There is an easier way but im also in class so I'll do it later!!!!

all four properties are satisfied, we can conclude that (M,d) is a metric space.

What is metric space?

In mathematics, a metric space is a set of objects called points, together with a function called the distance function or metric, that defines a notion of distance between any two points in the space. The metric satisfies certain conditions to ensure that it is a useful measure of the "distance" between points, such as being non-negative, symmetric, and satisfying the triangle inequality. Metric spaces are used to study properties of objects that can be thought of as having a notion of distance, such as Euclidean space, graphs, and networks.

Let's check each of these properties:

Non-negativity: This property holds since d(x, y) is defined to be 0 or 1, both of which are non-negative.

Identity of indiscernibles: This property also holds since d(x, y) is defined to be 0 if and only if x = y.

Symmetry: This property holds since d(x, y) = d(y, x) for any x, y in M.

Triangle inequality: For any x, y, z in M, there are three cases to consider:

If x = y or y = z, then d(x, y) + d(y, z) = d(x, z) = 1 by definition, and the inequality holds.

If x = z, then both sides of the inequality are 0.

If x, y, and z are all distinct, then d(x, y) + d(y, z) = 2 and d(x, z) = 1, so the inequality holds.

Since all four properties are satisfied, we can conclude that (M,d) is a metric space.

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The 98% confidence interval for the population mean is (1473.06, 1806.94).

The parameters needed to calculate a confidence interval are:

Sample mean (x) = 1640

Population standard deviation (σ) = 325

Sample size (n) = 25

Confidence level = 98%

To find the confidence interval, we can use the formula:

CI = x ± z*(σ/√n)

where z* is the z-score associated with the desired confidence level.

Since the confidence level is 98%, we need to use the z-score associated with a tail probability of 0.01 (0.5% on each tail). From the table given, this is z0.005 = 2.576.

Substituting the values, we get:

CI = 1640 ± 2.576*(325/√25) = 1640 ± 166.94

Therefore, the 98% confidence interval for the population mean is (1473.06, 1806.94).

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The CPMP mathematics methodology seems to be more effective on average at helping students solve word problems compared to the traditional method.

There is a greater variation in performance among students in the CPMP group. We can compare the CPMP and traditional math program groups' performance on solving word problems by looking at the mean and standard deviation.

1) Observe the mean scores:

- CPMP: 57.4

- Traditional: 53.9

The CPMP group has a higher mean score than the traditional group, indicating that students in the CPMP group performed better on average.

2) Observe the standard deviations:

- CPMP: 32.1

- Traditional: 28.5

The CPMP group has a higher standard deviation than the traditional group, meaning that the scores in the CPMP group are more spread out. This suggests there's a greater range of performance levels among students in the CPMP group.

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The value of x that would make M the midpoint of PQ if PM = 3x-1 and PQ = 5x+3 include the following: 2.

In Mathematics, the midpoint of a line segment with two end points can be calculated by adding each end point on a line segment together and then divide by two (2).

Since M is the midpoint of line segment PO, we have the following:

Line segment PM = Line segment PQ

3x - 1 = 5x + 3

5x - 3x = 3 + 1

2x = 4

x = 4/2

x = 2

PM = 3x - 1 = 3(2) - 1 = 6 - 1 = 5 units.

PQ = 5x + 3 = 5(2) + 3 = 10 + 3 = 13 units.

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We do not have sufficient evidence to conclude that 20-year-olds have more cavities than 30-year-olds.

First, we need to calculate the sample mean and standard deviation of the given data:

x = (6+7+7+8+7+8+9+6+5+6+7+8+7+6+9+8)/16 = 7

s = sqrt((Σ(x - x)²)/(n-1)) = sqrt((Σ(x²) - n(x)²)/(n-1)) = 1.247

Now, we can set up the hypothesis test:

H0: μ = 7 (20-year-olds have the same average number of cavities as 30-year-olds)

Ha: μ > 7 (20-year-olds have more cavities than 30-year-olds)

We will use a t-test since the population standard deviation is unknown and we have a small sample size (n = 16). The test statistic is:

t = (x - μ) / (s/sqrt(n)) = (7 - 7) / (1.247/sqrt(16)) = 0

The degrees of freedom is n-1 = 15. Using a t-table with α = 0.05 and df = 15, we find the critical value to be 1.753.

The p-value is the probability of getting a t-value as extreme or more extreme than the calculated t-value under the null hypothesis. Since our null hypothesis is that μ = 7 and our alternative hypothesis is that μ > 7, we have a one-tailed test. Using a t-table with df = 15, we find the p-value to be 0.5.

Since our p-value (0.5) is greater than α (0.05), we fail to reject the null hypothesis. We do not have sufficient evidence to conclude that 20-year-olds have more cavities than 30-year-olds.

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Answer:

The type of study conducted is an observational study. The response variable of the study is the concentration of the chemical.

Given: The solution to [tex]x^3[/tex] = [tex]-2-i[/tex] In polar form Is:

[tex]2 < 75^o, 2 < 195^o, 2 < 315^o[/tex]

Answer:

[tex]\large \boxed{\mathrm{ion \ even \ no \ fr}}[/tex]

Step-by-step explanation:

DO IT YOUR SELF [tex]\large \boxed{\mathrm{BOZO}}[/tex]

The required value of x in the given equation is -0.00047.

Let's first simplify the expression inside the parentheses:

-33x+1 = 1-33x

Now, we can substitute this back into the original equation and use order of operations (PEMDAS) to simplify:

4.76 - (23 x 51)-1(-33x+1) = 4.76 - (23/51)(1-33x)

= 4.76 - (23/51) + (23/17)x

Now, we want to solve for x. We'll start by isolating the term with x on one side of the equation:

(23/17)x = 4.76 - (23/51)

x =-0.00047

Therefore, the value of x in the given equation is -0.00047.

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The number of blocks needed to complete the big or full cube depends on size of cube. So, number of blocks required to complete it equals to 45.

A cube is a three-dimensional geometry, which may be solid or hollow and containing six equal squares. According to the shape of the cube, we can make a cube from any cubes. Now look at the cube image above. There is one more layer of blocks to fill in because the blocks are still 5 blocks by 4 blocks (not make a cube). We need to add another 25 blocks at the top to meet the cube definition. Some times we would often just count the missing blocks which is 20 here but after adding all 20 blocks in figure still it isn't a cube. So, 20 is wrong because the sides won’t be equal. The width and the length is made of 5 blocks but the height is just four blocks. So, it's need to add another 25 blocks the top to make it a cube. Hence, the correct answer is 45.

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Complete question:

The above figure complete the question.

How many blocks are needed to complete the full cube ?

Answer:

-8.5

Step-by-step explanation:

First we need to get the -4x by it self which means moving the 8 so what we need to do is subtract 8 from its self and what we do on one side we do to the other so 42-8=34 then the last thing to do is just divided 34 divided by -4 and we get

-8.5 as the answer.

PLS GIVE BRAINLIST MEAN THE WORLD

HAVE A GREAT DAY!!

We need to solve the equation 1 - Φ((L - Cm)/0.025) = 0.9265 for L. This can be done using a standard normal table or calculator.

(a) Let X be the length of the cylindrical bar. Then X ~ N(Cm, 0.25^2). We need to find P(X < 11.75).

Z = (X - Cm)/0.25 follows standard normal distribution.

P(X < 11.75) = P((X-Cm)/0.25 < (11.75-Cm)/0.25) = P(Z < (11.75-Cm)/0.25)

Using a standard normal table or calculator, we get P(Z < (11.75-Cm)/0.25) = Φ((11.75-Cm)/0.25)

where Φ is the cumulative distribution function of the standard normal distribution.

(b) The sample mean length, X, follows normal distribution with mean Cm and standard deviation σ/√n, where n = 100 is the sample size. So, X ~ N(Cm, 0.25/√100) = N(Cm, 0.025). Therefore, the mean of the sample mean length is Cm and the standard deviation of the sample mean length is 0.025.

(c) We need to find P(10.99 < X < 11.01), where X is the sample mean length.

Z = (X - Cm)/(0.025) follows standard normal distribution.

P(10.99 < X < 11.01) = P((10.99 - Cm)/(0.025) < Z < (11.01 - Cm)/(0.025))

Using a standard normal table or calculator, we get P((10.99 - Cm)/(0.025) < Z < (11.01 - Cm)/(0.025)) = Φ((11.01 - Cm)/(0.025)) - Φ((10.99 - Cm)/(0.025))

(d) Let L be the length such that 92.65% of the sample means are more than L. This means we need to find the value of L such that P(X > L) = 0.9265.

Z = (X - Cm)/(0.025) follows standard normal distribution.

P(X > L) = P(Z > (L - Cm)/0.025) = 1 - Φ((L - Cm)/0.025)

Therefore, we need to solve the equation 1 - Φ((L - Cm)/0.025) = 0.9265 for L. This can be done using a standard normal table or calculator.

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Answer:

The surface area is 70 yards

Step-by-step explanation:

The formula for surface area is (SA)=2lw+2lh+2hw. Meaning it would be 2 times (8 times 3 + 8 times 1 + 3 times 1) which equals 70 yards.

Answer:

m = +/- 5

Step-by-step explanation:

We can solve the equation by taking the fourth root of both sides.  

[tex]+/-\sqrt[4]{m^4}=+/-\sqrt[4]{625} \\m=5\\m=-5[/tex]

(5)(5)(5)(5) = 625

(-5)(-5)(-5)(-5) = 625

The +/- in the answers come from the fact that whenever you have a even exponent (e.g., x^2 or m^4), you always get a positive answer, even if the base you're raising to the particular exponent is negative

If Sheila’s test had a z-score of 2.2 then her test score was 89.6%.

We can use the formula for calculating the z-score of a value,

z = (x - μ) / σ, value we want to convert to a z-score is x, mean of the distribution is μ,  standard deviation of the distribution is σ and z score is z. In this case, we know that the average mark on the test was 72%, which means μ = 72. We also know that the standard deviation was 8%, which means σ = 8. We know that Sheila's z-score was 2.2,

We can rearrange the formula to solve for x,

x = μ + zσ

Substituting in the values we know,

x = 72 + 2.2 * 8

x = 72 + 17.6

x = 89.6

Therefore, Sheila's test score was 89.6%.

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a. E[Y] = (0)(0.2) + (2)(0.5) + (4)(0.3) = 1.8 is the expected value for Y.

b. The cumulative distribution function of X+Y is P(X+Y = k) = Σ P(X=i)P(Y=k-i).

c. P(X=Y) is 0.3654.

d. Calculation is not correct. 3.6 is the correct value of E[XY].

In mathematics, a variable is defined as an alphabetic character that expresses a numerical value or number. A variable is used to represent an unknown quantity in algebraic equations.

(a) The expected value of Y can be calculated as E[Y] = (0)(0.2) + (2)(0.5) + (4)(0.3) = 1.8.

(b) To find the cumulative distribution function of X+Y, we first note that the sum of two independent random variables has a probability mass function given by the convolution of their respective probability mass functions. That is,

P(X+Y = k) = Σ P(X=i)P(Y=k-i)

where the sum is taken over all possible values of i such that both P(X=i) and P(Y=k-i) are nonzero. Using this formula, we can compute the cumulative distribution function of X+Y as:

F(x) = P(X+Y ≤ x) = Σ P(X+Y = k) for k ≤ x

     = Σ Σ P(X=i)P(Y=k-i) for k ≤ x

     = Σ P(X=i) Σ P(Y=k-i) for k ≤ x

     = Σ P(X=i) [tex]F_Y[/tex](x-i)

where [tex]F_Y[/tex](x) is the cumulative distribution function of Y. Since X has a Poisson(2) distribution, we can compute the cumulative distribution function of X+Y as:

F(x) = Σ P(X=i) F_Y(x-i)

     = Σ [tex]e^{(-2)} (2^i / i!) (0.2P(Y=x-i=0) + 0.5P(Y=x-i=2) + 0.3P(Y=x-i=4))[/tex]

where P(Y=x-i=k) is the probability mass function of Y.

(c) P(X=Y) can be calculated as:

P(X=Y) = Σ P(X=i, Y=i)

         = Σ P(X=i)P(Y=i) (since X and Y are independent)

         = Σ [tex]e^{(-2)} (2^i / i!) (0.2)(0) + (0.5)(e^(-2))(2^i / i!) + (0.3)(e^{(-2)})(2^i / i!)^2[/tex]

         = [tex]e^{(-4)} (0 + 0.5(2e^2/2) + 0.3(4e^2/4))[/tex]

         = 0.3654

(d) The student's calculation is not correct. To see why, let's first note that E[XY] can be computed as:

E[XY] = E[E[XY|X]] = E[XE[Y|X]]

where E[Y|X] is the conditional expected value of Y given X. Since X and Y are independent, we have E[Y|X] = E[Y] = 1.8. Therefore,

E[XY] = E[XE[Y|X]] = E[X(1.8)] = 2(1.8) = 3.6

So the correct value of E[XY] is 3.6, which is twice the value calculated by the student. The mistake the student made was in assuming that E[XY] is equal to the product of E[X] and E[Y]. This is only true if X and Y are uncorrelated, which is not the case here since X and Y are independent but not identically distributed.

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