Consider the following expression -2m(m+n-4)+5(-2m+2n)+n(m+4n-5) which of the following is an equivalent expression

The table shows how an elevator 500 feet above the ground is descending at a steady rate. Which equation represents the height,

Gennadij [26K]

This is the concept of algebra, given that the elevator is 500ft above the ground and it is descending at a steady rate of 5ft/sec. Then height h, at time t of the elevator movement can be modeled by the equation:
h(t)=-5t+500.
The correct answer is h(t)=-5t+500

5 0

1 year ago

Joaquin and Trisha are playing a game in which the lower median wins the game. Their scores are shown below.

iragen [17]

Median is defined as the middle term when the scores are arranged in increasing/decreasing order.

Joaquin's scores: 58, 62, 72, 75, 85, 91 Median: 73.5
Trisha's scores: 55, 74, 76, 90, 91, 92 Median: 83

The answer is letter A.

3 0

1 year ago

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The percentage of body fat of a random sample of 36 men aged 20 to 29 found a sample mean of 14.42. Find a 95% confidence interv

Rina8888 [55]

Answer:

$14.42-1.96\frac{6.95}{\sqrt{36}}=12.150$

$14.42+ 1.96\frac{6.95}{\sqrt{36}}=16.690$

So on this case the 95% confidence interval would be given by (12.150;16.690)

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".

$\bar X=14.42$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=6.95$ represent the population standard deviation

n=36 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

Now we have everything in order to replace into formula (1):

$14.42-1.96\frac{6.95}{\sqrt{36}}=12.150$

$14.42+ 1.96\frac{6.95}{\sqrt{36}}=16.690$

So on this case the 95% confidence interval would be given by (12.150;16.690)

5 0

2 years ago

Simplify: StartRoot 64 r Superscript 8 Baseline EndRoot

patriot [66]

Answer:

8r^4

Step-by-step explanation:

$\sqrt{64r^8} =\sqrt{(8r^4)^2}=\boxed{8r^4}$

5 0

2 years ago

There are seven boys and five girls in a class. The teacher randomly selects three different students to answer questions. The f

Aleks [24]

The probability of picking one girl would be $\frac{5}{12}$ . That is because there are 5 girls out of the 12 students, and the probability of an event occuring is: $\frac{\text{# of things you want}}{\text{# of things are possible}}$ .

Using that same logic, the next student should be easier. We reduced the student population by 1, so we have 11 possible ways it can happen now instead of 12, so that gives us: $\frac{7}{11}$ , for the probability of picking a boy as the second pick.

And lastly, using the same logic shown above, the probability of picking a girl on the third pick would be: $\frac{4}{10}$ .

We are not done, though. We have the separate probabilities, but now we have to multiply then together to figure out the probability of this exact event happening:

$\frac{5}{12}*\frac{7}{11}*\frac{4}{10}=\frac{140}{1320}$

Which when reduced is:

$\frac{7}{66}$

4 0

2 years ago

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