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3 years ago

4x- 2y = 8 2x + y =2

Mathematics

1 answer:

Juli2301 [7.4K]3 years ago

5 0

Answer:

x = 3/2 , y = -1

Step-by-step explanation:

I'm assuming that you are being asked to solve the system of equations for x and y.

given:

4x- 2y = 8 ---------------(1)

2x + y =2 -----------------(2)

We can solve this by elimination:

multiple (2) by 2, we get:

2(2x + y) =2(2)

4x + 2y = 4 ------------(3)

(1) + (3) , we get:

(4x- 2y) - (4x + 2y) = 8 + 4

8x = 12 (divide both sides by 8)

x = 12/8

x = 3/2 answer, substitute this into (2)

2(3/2) + y =2

3 + y = 2 (subtract 3 from both sides)

y = 2 - 3

y = -1 answer

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I have 100 items of product in stock. The probability mass function for the product's demand D is P(D=90)=P(D=100)=P(D=110)=1/3.

masya89 [10]

Answer:

The probability mass function for the items sold is

$P_X(k) = \left \{ {\frac{1}{3} \, \, \, {k=90} \atop \, \frac{2}{3} \, \, \, {k=100}} \right.$

The mean is 96.667

The variance is 22.222

b) The probability mass function for the unfilled demand due to lack of stock is

$P_Y(k) = \left \{ {\frac{2}{3} \, \, \, {k=0} \atop \, \frac{1}{3} \, \, \, {k=10}} \right.$

The mean is 3.333

The variance is 33.333

Step-by-step explanation:

If the demand is higher than 100, then you will sell 100 items only. Thus, there is a probability of 1/3+1/3 = 2/3 that you will sell 100 items, while there is a probability of 1/3 that you will sell 90.

The probability mass function for the items sold is

$P_X(k) = \left \{ {\frac{1}{3} \, \, \, {k=90} \atop \, \frac{2}{3} \, \, \, {k=100}} \right.$

The mean is 1/3 * 90 + 2/3 * 100 = 290/3 = 96.667

The variance is V(X) = E(X²)-E(X)² = (1/3*90² + 2/3*100²) - (290/3)² = 200/9 = 22.222

b) If order to be unfilled demand, you need to have a demand of 110, which happens with probability 1/3. In that case, the value of the variable, lets call it Y, that counts the amount of unfilled demand due to lack of stock is 110-100 = 10. In any other case, the value of Y is 0, which would happen with probability 1-1/3 = 2/3. Thus

$P_Y(k) = \left \{ {\frac{2}{3} \, \, \, {k=0} \atop \, \frac{1}{3} \, \, \, {k=10}} \right.$

The mean is 2/3 * 0 + 1/3 * 10 = 10/3 = 3.333

The variance is 2/3*0² + 1/3*10² = 100/3 = 33.333

4 0

3 years ago

Benito wrote the equations shown about the figure. Explain Benito’s errors.

Minchanka [31]

Answer:

Benito's error was using the equal sign (=) instead of the congruency symbol (≅).

Explanation:

Benito's error was using the equal sign (=) instead of the congruency symbol (≅).

The congruency symbol (≅) means that the elements (segments, angles or figures in general) have the same measure, i.e. they have equal lengths for the segments or equal measure for the angles.

For instance, it is an error saying that the segment AB is equal to the segment BC because, as you clearly see in the picture, they are not same; they have the same length but they are joining different points, that makes them different in essence, although they have the same length. They would be equal only if they are the same figure.

In mathematics, you must not say that two different segments or two different angles are equal but they are congruent, which means that their lengths are equal. The use of equal is reserved for numbers and variables, not for figures like segment, points, angles, polygons.

7 0

3 years ago

In the distribution, the first quartile,median and mean are 30.8,48.5 and 42.0 respectively. If the co efficient skewness is -0.

finlep [7]

Answer:

The third quartile is 56.45

Step-by-step explanation:

The given parameters are;

The first quartile, Q₁ = 30.8

The median or second quartile, Q₂ = 48.5

The mean, $\bar x$ = 42.0

Coefficient of skewness = -0.38

The Bowley's coefficient of skewness (SK) is given as follows;

$SK = \dfrac{Q_3 + Q_1 - 2 \times Q_2}{Q_3 - Q_1}$

Plugging in the values, we have;

$-0.38 = \dfrac{Q_3 + 30.8 - 2 \times 48.5}{Q_3 - 30.8}$

Which gives;

-0.38×(Q₃ - 30.8) = Q₃ + 30.8 - 2 × 48.5

11.704 - 0.38·Q₃ = Q₃ - 66.2

1.38·Q₃ = 11.704 + 66.2 = 77.904

Q₃ = 56.45

The third quartile = 56.45.

5 0

3 years ago

For the geometric series given by 5 + 10 + 20+ . . . , which of the following statements is FALSE?

slava [35]

Answer:

All statements are true

Step-by-step explanation:

1. The statement $S_{500}>S_{499}$ is true, because $S_{499}$ is the sum of first 499 terms, $S_{500}$ is the sum of first 500 terms, and all these terms are positive, then the sum of smaller number of terms is less than the sum of larger number of terms.

2. The statement $S_{500}>a_{500}$ is true, because $S_{500}$ is the sum of first 500 terms, $a_{500}$ is 500th term and the sum of 500 terms is greater than the 500th term.

3. The statement $S_1=a_1$ is true, because $S_1$ is the sum of first 1 term that is exactly $a_1.$

All statements are true.

5 0

3 years ago

What is the sale price for your purchase if you have a 20% off coupon and you buy a shirt for $19.99 and pants for $10.

Andrew [12]

Answer: I believe it is $23.99

Explanation:
19.99+10= 29.99
29.99x0.2= 5.992
29.99-5.99= $23.99

I hope this helped!

4 0

3 years ago