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4 years ago

ONE QUESTION ONLY!!!

2 answers:

6 0

Let first number = X and 2nd number = Y

Equation 1: 5X + 8Y = -13

Equation 2: 5X + 10Y = -15

Multiply equation 1 by -1 to get: -5X + -8Y = 13

Now add the 2 equations together:
-5X + 5X = 0

-8Y + 10Y = 2Y

13 + -15 = -2

The total of the 2 equations is 2Y = -2

divide both sides by 2 to solve for Y
Y = -2 / 2
Y = -1
Now we know the 2nd number is -1, so replace Y in the 1st equation and solve for X

5X +8(-1) = -13

5x + -8 = -13

Add 8 to both sides:
5x = -5

Divide both sides by 5 to get x

X = -5 / 5
X = -1

Both numbers are -1

To check replace X and Y with -1 and solve:

1st equation: 5(-1) +8(-1) = -5 + -8 = -13 TRUE

2nd equation: 5(-1) +10(-1) = -5 + -10 = -15 TRUE

Both numbers are -1

Sedaia [141]4 years ago

3 0

1st number be x, 2nd number be y

Adding 5 times the first number and 8 times the second number gives a total of -13

so 5x+8y=-13

Adding 5 times the first number and 10 times the second number gives -15

so 5x+10y=-15

subtracting the above two eqns

(5x+8y)-(5x+10y) = -13-(-15)

-2y=2

y=-1

put back in first eqn 5x+8(-1)=-13

5x=-5

x=-1

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Answer:

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Step-by-step explanation:

-6 1/10=-14+c

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-14+c +14= -61/10 +14

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3 years ago

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3 years ago

The following table summarises the data from a survey on the ownership of iPods among families with different levels of income.

AURORKA [14]

The two nominal variables are related.

The following table summarises the data from a survey on the ownership of iPods among families with different levels of income.

Ownership C1 C2 C3

No 40 32 48

Yes 30 48 52

The first thing to do in order to determine if they are related or not is to state our null and alternative hypothesis

Null hypothesis

$\mathbf{H_o: Two \nomial \ variables \ are \ related}$

Alternative hypothesis

$\mathbf{H_a: Two \nomial \ variables \ are \ not \ related}$

Using the Chi-square test statistics which can be expressed by using the formula

$X ^2 = \sum \dfrac{(O-E)^2}{E}$

Ownership C1 C2 C3 Total

No 40 32 48 120

Yes 30 48 52 130

Total 70 80 100 250

The expected values are calculated as:

$\mathsf{E_{a,b} = \dfrac{(row \ total \times column \ total )}{grand \ total }}$

$\mathsf{E_{1,1} = \dfrac{(70 \times120 )}{250 }}$

$\mathsf{E_{1,1} = 33.6}$

$\mathsf{E_{1,2} = \dfrac{(70 \times130 )}{250 }}$

$\mathsf{E_{1,2} = 36.4}$

$\mathsf{E_{2,1} = \dfrac{(80 \times120 )}{250 }}$

$\mathsf{E_{2,1} = 38.4}$

$\mathsf{E_{2,2} = \dfrac{(80 \times 130 )}{250 }}$

$\mathsf{E_{2,2} = 41.6}$

$\mathsf{E_{3,1} = \dfrac{(100 \times120 )}{250 }}$

$\mathsf{E_{3,1} = 48}$

$\mathsf{E_{3,2} = \dfrac{(70 \times130 )}{250 }}$

$\mathsf{E_{3,2} = 52}$

∴ Using the Chi-square test statistics, we have:

$X ^2 = \sum \dfrac{(O-E)^2}{E}$

$X ^2 = \Bigg( \dfrac{(40-33.6)^2}{33.6}+ \dfrac{(30-36.4)^2}{36.4}+ \dfrac{(32-38.4)^2}{38.4}+ \dfrac{(48-41.6)^2}{41.6} + \dfrac{(48-48)^2}{48}+ \dfrac{(52-52)^2}{52} \Bigg)$

$X ^2 = \Bigg( \dfrac{40.96}{33.6}+ \dfrac{40.96}{36.4}+ \dfrac{40.96}{38.4}+ \dfrac{40.96}{41.6} + \dfrac{0}{48}+ \dfrac{0}{52} \Bigg)$

$X ^2 = \Bigg( 1.2190+ 1.1253+ 1.0667+ 0.9846+0+ 0 \Bigg)$

$\mathbf{X ^2 =4.3956}$

The degree of freedom df = ((r - 1) × (c - 1))

= (3 - 1) (2 -1 )

= 2 × 1

= 2

∴

Assuming the level of significance = 5%

The p-value of the Chi-square test statistics at df of 2 is:

= $\mathbf{P(X^2 > 4.3956) \implies 0.111}$

Therefore, we can conclude that since the p-value (0.111) is greater than the level of significance (0.05), we fail to reject the null hypothesis.

Hence, the two nominal variables are related.

Learn more about Chi-square test statistics here:

brainly.com/question/2365682?referrer=searchResults

7 0

3 years ago

A family went out to dinner. their bill was $65.00. they left a 15% tip on top of the bill. which amount is closest to the total

devlian [24]

65 divided by 15 =4.3

8 0

3 years ago

Read 2 more answers

Mario and Luigi were selling coupon books for the Video game club fundraiser. Apparently, Mario is a much better salesperson, be

sattari [20]

Answer: the total number of coupon books sold is 20.

Step-by-step explanation:

Let x represent the number of coupon books that Mario sold.

Let y represent the number of coupon books that Luigi sold.

Apparently, Mario is a much better salesperson, because he sold 4 times as many coupon books as Luigi. This is expressed as

x = 4y

If Luigi sold 12 fewer coupon books than Mario, the expression would be

x = y + 12 - - - - - - - - - - -- -1

Substituting x = 4y into equation 1, it becomes

4y = y + 12

4y - y = 12

3y = 12

y = 12/3

y = 4

x = 4y = 4 × 4

x = 16

The total number of coupon books that the two boys sold is

4 + 16 = 20

4 0

4 years ago