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3 years ago

Help me on this math problem

Mathematics

1 answer:

Anon25 [30]3 years ago

4 0

Answer:

D: t = u/9 + 7 (that is simplified all of the way) for your case it is t = u + 63/9 so D

Explanation:

Just ask if you need an explanation. Also, does anyone do LD debate?

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Find the first five terms of each arithmetetic sequence describe a1 = -12 d = 5

Fudgin [204]

Answer:

- 12, - 7, - 2, 3, 8

Step-by-step explanation:

The general terms of an arithmetic sequence are

a, a + d, a + 2d + ....... + a + (n - 1 )d

To obtain consecutive terms in the sequence add d = 5 to the previous term

$a_{1}$ = - 12

$a_{2}$ = - 12 + 5 = - 7

$a_{3}$ = - 7 + 5 = - 2

$a_{4}$ = - 2 + 5 = 3

$a_{5}$ = 3 + 5 = 8

4 0

3 years ago

4- A manufacturing process produces items whose weights are normally distributed. It is known that 22.57% of all the items produ

galben [10]

Answer:

$\\ \mu = 118\;grams\;and\;\sigma=30\;grams$

Step-by-step explanation:

We need to use z-scores and a standard normal table to find the values that corresponds to the probabilities given, and then to solve a system of equations to find $\\ \mu\;and\;\sigma$ .

<h3>First Case: items from 100 grams to the mean</h3>

For finding probabilities that corresponds to z-scores, we are going to use here a <u>Standard Normal Table </u><u><em>for cumulative probabilities from the mean </em></u><em>(Standard normal table. Cumulative from the mean (0 to Z), 2020, in Wikipedia) </em>that is, the "probability that a statistic is between 0 (the mean) and Z".

A value of a z-score for the probability P(100<x<mean) = 22.57% = 0.2257 corresponds to a value of z-score = 0.6, that is, the value is 0.6 standard deviations from the mean. Since this value is <em>below the mean</em> ("the items produced weigh between 100 grams up to the mean"), then the z-score is negative.

Then

$\\ z = -0.6\;and\;z = \frac{x-\mu}{\sigma}$

$\\ -0.6 = \frac{100-\mu}{\sigma}$ (1)

<h3>Second Case: items from the mean up to 190 grams</h3>

We can apply the same procedure as before. A value of a z-score for the probability P(mean<x<190) = 49.18% = 0.4918 corresponds to a value of z-score = 2.4, which is positive since it is after the mean.

Then

$\\ z =2.4\;and\; z = \frac{x-\mu}{\sigma}$

$\\ 2.4 = \frac{190-\mu}{\sigma}$ (2)

<h3>Solving a system of equations for values of the mean and standard deviation</h3>

Having equations (1) and (2), we can form a system of two equations and two unknowns values:

$\\ -0.6 = \frac{100-\mu}{\sigma}$ (1)

$\\ 2.4 = \frac{190-\mu}{\sigma}$ (2)

Rearranging these two equations:

$\\ -0.6*\sigma = 100-\mu$ (1)

$\\ 2.4*\sigma = 190-\mu$ (2)

To solve this system of equations, we can multiply (1) by -1, and them sum the two resulting equation:

$\\ 0.6*\sigma = -100+\mu$ (1)

$\\ 2.4*\sigma = 190-\mu$ (2)

Summing both equations, we obtain the following equation:

$\\ 3.0*\sigma = 90$

Then

$\\ \sigma = \frac{90}{3.0} = 30$

To find the value of the mean, we need to substitute the value obtained for the standard deviation in equation (2):

$\\ 2.4*30 = 190-\mu$ (2)

$\\ 2.4*30 - 190 = -\mu$

$\\ -2.4*30 + 190 = \mu$

$\\ \mu = 118$

7 0

3 years ago

Please help me with Part C of this question!!!

anzhelika [568]

Answer:

a. 3/4 inches per minute

b. -1 1/8 inches per minute

c. B is fastest; 1 1/8 is more than 3/4

Step-by-step explanation:

A <em>change</em> is a <em>difference</em>. A <em>rate of change</em> is <em>one difference divided by another</em>, usually the change in y-value divided by the change in x-value.

The change in elevation is the difference between the elevation at the end of the period (6 inches) and the elevation at the beginning of the period (3 inches). The change in time period is the difference between the end time (8 min) and the beginning time (4 min).

change in elevation per minute = (6 -3 inches)/(8 -4 min)

= (3 inches)/(4 min) = 3/4 inches/minute

Similarly, ...

change in elevation per minute = (3 -7 1/2 inches)/(18 -14 min)

= (-4 1/2 inches)/(4 min) = -1 1/8 inches/minute

We know that 3/4 is more than -1 1/8, but when we talk about the "fastest rate of change", we're generally interested in the magnitude--the value without the sign. That means we understand a rate of change of -1 1/8 inches per minute to be "faster" than a rate of change of 3/4 inches per minute.

The rate of change from Part B is fastest. 1 1/8 inches per minute is more than 3/4 inches per minute.

6 0

2 years ago

What expression best estimates -18 1/4 ÷ 2 2/3<br>a. 18÷3<br>b. -18÷3<br>c. -18÷(-3)<br>d. 18÷(-3)

agasfer [191]

B) because if you round your numbers, -18 1/4 is -18 and 2 2/3 rounds up to positive 3

8 0

3 years ago

The cities D, E, and Flie, in respective order, approximately in a straight line. The distance from city D to city E is 125 mile

Yakvenalex [24]

Answer:

Step-by-step explanation: subtract 160 and 125 and you’ll get 35

4 0

3 years ago