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3 years ago

9

casey has n nickels.meghan has 4 times as many nickels as casey has.write an expression for the total number of nickels casey an

d meghan have.then simplify the expression.

1 answer:

Amanda [17]3 years ago

6 0

Answer:

5n

Step-by-step explanation:

Summarizing what we know:

Casey has n nickels, and Meghan 4 times as many: 4n

Then the total number of nickets these two people have is n + 4n, or 5n.

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a delivery man weighs 200 pounds. he is delivering cartons that each weigh 48 pounds. he wants to know how many cartons he can s

Anastasy [175]

The inequality is:

48 c + 200 ≤ (the maximum load allowed on the elevator) .

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3 years ago

For a certain river, suppose the drought length Y is the number of consecutive time intervals in which the water supply remains

AnnZ [28]

Answer:

a) There is a 9% probability that a drought lasts exactly 3 intervals.

There is an 85.5% probability that a drought lasts at most 3 intervals.

b)There is a 14.5% probability that the length of a drought exceeds its mean value by at least one standard deviation

Step-by-step explanation:

The geometric distribution is the number of failures expected before you get a success in a series of Bernoulli trials.

It has the following probability density formula:

$f(x) = (1-p)^{x}p$

In which p is the probability of a success.

The mean of the geometric distribution is given by the following formula:

$\mu = \frac{1-p}{p}$

The standard deviation of the geometric distribution is given by the following formula:

$\sigma = \sqrt{\frac{1-p}{p^{2}}$

In this problem, we have that:

$p = 0.383$

So

$\mu = \frac{1-p}{p} = \frac{1-0.383}{0.383} = 1.61$

$\sigma = \sqrt{\frac{1-p}{p^{2}}} = \sqrt{\frac{1-0.383}{(0.383)^{2}}} = 2.05$

(a) What is the probability that a drought lasts exactly 3 intervals?

This is $f(3)$

$f(x) = (1-p)^{x}p$

$f(3) = (1-0.383)^{3}*(0.383)$

$f(3) = 0.09$

There is a 9% probability that a drought lasts exactly 3 intervals.

At most 3 intervals?

This is $P = f(0) + f(1) + f(2) + f(3)$

$f(x) = (1-p)^{x}p$

$f(0) = (1-0.383)^{0}*(0.383) = 0.383$

$f(1) = (1-0.383)^{1}*(0.383) = 0.236$

$f(2) = (1-0.383)^{2}*(0.383) = 0.146$

Previously in this exercise, we found that $f(3) = 0.09$

So

$P = f(0) + f(1) + f(2) + f(3) = 0.383 + 0.236 + 0.146 + 0.09 = 0.855$

There is an 85.5% probability that a drought lasts at most 3 intervals.

(b) What is the probability that the length of a drought exceeds its mean value by at least one standard deviation?

This is $P(X \geq \mu+\sigma) = P(X \geq 1.61 + 2.05) = P(X \geq 3.66) = P(X \geq 4)$ .

We are working with discrete data, so 3.66 is rounded up to 4.

Either a drought lasts at least four months, or it lasts at most thee. In a), we found that the probability that it lasts at most 3 months is 0.855. The sum of these probabilities is decimal 1. So:

$P(X \leq 3) + P(X \geq 4) = 1$

$0.855 + P(X \geq 4) = 1$

$P(X \geq 4) = 0.145$

There is a 14.5% probability that the length of a drought exceeds its mean value by at least one standard deviation

8 0

3 years ago

The life of a manufacturer's compact fluorescent light bulbs is normal, with mean 12,000 hours and standard deviation 2,000 hour

vitfil [10]

Z value is a numerical measurement that describe a value relationship to the mean of a group of values. The standard deviations is 1.25 above the mean is 14,500 hours.

<h3>Given information-</h3>

The mean for the bulb is 12,000 hours.

The standard deviation for the bulb is 2000 hours.

Sample value is 14500.

To find out the how many standard deviation is 14500 mean away from the mean the z value of the mean should be calculated.

<h3>Z value</h3>

Z value is a numerical measurement that describe a value relationship to the mean of a group of values. Z value is the ratio of the difference of the sample value $x$ and mean $\mu$ to the standard deviation. Thus the z value for the given mean $\sigma$ is,

$z=\dfrac{x-\mu}{\sigma}$

$z=\dfrac{14500-1200}{2000}$

$z=1.25$

Thus the standard deviations is 1.25 above the mean is 14,500 hours.

Learn more about the z value here;

brainly.com/question/62233

4 0

3 years ago

Can someone help me out ? Don't just guess the answer :(

Monica [59]

1) 2m+6 / m² + 7m - 12 + (m+2)/(m+4)

= 2(m+3) / (m+4)(m+3) + (m+2)/(m+4)

= 2/(m+4) + (m+2)/(m+4)

= 2+m+2 / (m+4)

= m+4 / m+4

= 1 [ Option A ]

Answer 2) 3/ (x+4) + 7/ (x-3)

= 3(x-3) + 7(x+4)/ (x² +x - 12)

= 3x-9 + 7x + 28 / (x² +x - 12)

= 10x + 19 / (x² +x - 12) [ Option A ]

Hope this helps!

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3 years ago

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Use the figure.<br> What is the measure of angle 2?

zhuklara [117]

Answer:

3x+9

Step-by-step explanation:

i think since it is across from there

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