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3 years ago

Find two numbers with a sum of 20 and a difference of 14.. . A. 4 and 18. . B. –3 and –17. . C. 2 and 16. . D. 3 and 18

2 answers:

6 0

From the given equation
X+Y=20-->i
X-Y=14--->ii
add eq i and eq ii
2x=34
x=17
putting the value of x=17 in eq i
17+y=20
then y = 3 so the right answer is
17 and 3

zmey [24]3 years ago

6 0

Hello,

A) 4+18=22 no
B) -3+(-17)=-20 no
C) 2+16=18 no
D) 3+18=21 no

If E is 3 and 17 then YES!!!!!

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Please and thank you

NemiM [27]

Y+3=1/4x-1/4
0.25x-y=3-0.25
0.25x-y=2.75

8 0

3 years ago

Your state is considering raising the legal age for consumption of alcoholic beverages to 21 years old. How large a sample size

julsineya [31]

Answer:

$n=\frac{0.5(1-0.5)}{(\frac{0.01}{2.58})^2}=16641$

And rounded up we have that n=16641

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Solution to the problem

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 99% of confidence, our significance level would be given by $\alpha=1-0.99=0.01$ and $\alpha/2 =0.005$ . And the critical value would be given by:

$z_{\alpha/2}=-2.58, t_{1-\alpha/2}=2.58$

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

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

And on this case we have that $ME =\pm 0.01$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

For this case we can use as estimator for the proportion $\hat p =0.5$ , since we don't have any other previous info. And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.01}{2.58})^2}=16641$

And rounded up we have that n=16641

8 0

3 years ago

Questions 1-6 please

MakcuM [25]

Question 1 is $6 \sqrt{2}$
question 2 is $4 \sqrt{5} + 3 \sqrt{2}$
question 3 is $6 \sqrt{2}$
question 4 is $8 \sqrt{3}$
question 5 is $\frac{ \sqrt{3}}{2}- \sqrt{3}$
question 6 is $5$

6 0

4 years ago

Of the 12 temporary employees in a certain company, 4 will be hired as permanent employees. If 5 of the 12 temporary employees a

Ivenika [448]

Answer:

<h2>70 possible groups</h2>

Step-by-step explanation:

Given the total number of employee to be equal to 12 temporary employee.

Number of women employee = 5 women

Number of men employee = 12 - 5 = 7 men

If 4 will be hired as permanent employees, the possible ways they can be grouped so that the 4 temporary employees consists of 3 women and 1 man can be done by applying the combination formula.

Combination has to do with selection. For example, if r objects are to be selected from n pool of similar objects, this can be done in <em>nCr </em>different ways.

$nCr = \frac{n!}{(n-r)!r!}$

According to question, we are to select 3 women from 5 women and 1 man from 7 men. Based on similarity in sex, this can be done in (5C3* 7C1) different ways .

$5C3 * 7C1\\= \frac{5!}{(5-3)!3!} * \frac{7!}{(7-1)!1!}\\\\= \frac{5!}{2!3!} * \frac{7!}{6!1!}\\\\= \frac{5*4*3!}{3!*2} * \frac{7*6!}{6!*1}\\\\= \frac{20}{2} * \frac{7}{1}\\ \\= 10*7\\\\= 70\ possible\ groups$

8 0

4 years ago

Constance will put $500 in a savings account. Which option should she choose so that she will have the most money

pav-90 [236]

2 years at 7% is the answer

5 0

3 years ago

Read 2 more answers