NEED HELP ASAP WILL GIVE BRAINLY

ziro4ka [17]

Ha. That looks alot like i-ready. (i-ready sucks butt.)

But the horror that is i-ready aside, your answer is the third one : The proportion of grandparents that feel safe entering their account information online is 0.32.

32% converted to a decimal is 0.32, and 68% converted to a decimal is 0.68. That would mean that the proportion for grandparents that feel safe doing so is 0.32, and the number of grandparents that don't feel safe doing so is 0.68.

8 0

3 years ago

Work out the time taken, in minutes, for a 68km journey at an average speed of 85km/h

vovikov84 [41]

Answer:

48 minutes

Step-by-step explanation: Time taken is distance divided by speed, so 68/85 is 0.8. 0.8 is equal to 4/5. 4/5 of an hour is 48 minutes.

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

Can someone help me with this please?

GarryVolchara [31]

Answer:

16.49

Step-by-step explanation:

21^2 - 13^2 = 272

square root 272 = 16.49

7 0

2 years ago

Which equation can pair with 3x + 4y = 8 to create a consistent and independent system? 6x + 8y = 16 –3x – 4y = –6 6x – 3y = 2 –

pogonyaev

The right answer is C)

Consistent and independent system of two linear equations is a system such that there is only one solution for the system, that is, the two straight lines cross at a point. So we can analyze each case and I have attached some graphs to provided you with examples. Those graphs aren't about the equations but it's about general cases:

A) Consistent and dependent. If we divide this given equation by 2 we get the same line. (See Figure 1)

B) Inconsistent. No solutions. (See Figure 2)

C) Consistent and Independent. (See Figure 3)

D) Consistent and dependent.

7 0

2 years ago

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