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3 years ago

Which tipe of this method???

Mathematics

1 answer:

Hoochie [10]3 years ago

6 0

Answer:

It appears to be substitution

Step-by-step explanation:

I think you are talking about system of equations

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9. Tobias ran 3 miles. How many millimeters did he run? (1 mile = 1,610 meters)

Gekata [30.6K]

Welcome to Brainly! I'm happy to help!

We see that there are 1,610 meters in a mile. However, we are looking for millimeters, not meters. But, knowing the meters will help us out.

A millimeter is a very small measurement. There are 1,000 millimeters in 1 meter. A meter is much larger. So, if we want to convert 1,610 meters to millimeters, there are going to be way more millimeters because they are so minute.

This means that we will have to multiply. We know that there are 1,000 millimeters in 1 meter, so if we multiply our meters by 1,000 (which is basically just adding 3 zeros), we will get the number of millimeters in one mile!

1,610×1,000=1,610,000 (one million six hundred and ten thousand!)

Don't forget that we are looking for 3 miles though, so we can take the number of millimeters in one mile and multiply by three.

1,610,000×3=4,830,000 (four million eight hundred and thirty thousand!)

So, Tobias ran 4,830,000 millimeters!

Have a wonderful day and keep on learning! :D

7 0

3 years ago

Determine the sample size needed to construct a 90% confidence interval to estimate the population proportion when p = 0.65 and

WINSTONCH [101]

Answer:

n=170

Step-by-step explanation:

1) Notation and definitions

$n$ random sample taken (variable of interest)

$\hat p=0.65$ estimated proportion.

$p$ true population

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

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

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 90% of confidence, our significance level would be given by $\alpha=1-0.90=0.1$ and $\alpha/2 =0.05$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.64$

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 $ME =\pm 0.06$ 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)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.65(1-0.65)}{(\frac{0.06}{1.64})^2}=169.968$

And rounded up we have that n=170

6 0

3 years ago

When x increases from a to a +2, y increases by a factor of 1/4

Troyanec [42]

Answer:

y=7* (0.5)^x

Step-by-step explanation:

We are given that when x increases from 'a' to 'a+2' then y must increase by a factor of 1/4=0.25.

i.e. when x=a and x'=a+2.

then y/y=0.25 where y' is the function after putting x' to the old function.

8 0

3 years ago

A family needs to cross a river in a small raft.

serg [7]

Answer:

so basically you can take more than one trip you can take the mother and the bag at the same time

Step-by-step explanation:

and then you can get the daughter in the son at the same time and then for the final trip you take the father by himself

8 0

2 years ago

Find the value of x shown below

irakobra [83]

Angles opposite to the equal sides of an isosceles triangle are equal, so the third angle in this triangle is also 61. Now, you know all the angles in the triangle, you can use the Triangle Sum Theorem, which says that all the angles in a triangle add up to 180.

x + 61 + 61 = 180

x + 122 = 180

x = 58

Hope this helped!

7 0

2 years ago

Which tipe of this method???​

Which tipe of this method???