Which of the following is the correct representation of the polynomial

If 1 is added to a number and the sum is tripled, the result is 17 more than the number. Find the number

bearhunter [10]

Form an equation. Start by representing the number you want to find as X. Now add 1.
X + 1
Now we need to triple it. That basically means multiply X+1 by 3. You can write that as:
3 (X + 1)
Now we write out that the result is 17 more than the number we want to find. So set an equals sign up
3 (X + 1) =
And now write X + 17
3 (X + 1) = X + 17

Now we solve for X.
Firstly, let's get rid of the X on the right.
Remember, if we want to get rid of a number of variable on one side, we need to use opposites, and do the same to the other side of the equation.
In this case, we have a positive X on the right. To get rid of that, we subtract X from both sides. This will leave us with:
2x + 3 = 17
Now let's get rid of the +3 on the left. To do this, we subtract 3 from both sides of the equation.
2x = 17 - 3
2x = 14
Now we just need to get X by itself. The 2 in front of the X multiplies X by 2. Therefore, to get X on its own, we need to divide 2x by 2, which just gives us 2.
We also need to divide the other side by 2, because if we do something on one side, we need to do something on the other too. So divide 14 by 2, and we get 7.
X = 7

But before we celebrate, let's double check the answer. Add 1 to 7. This gives us 8. Triple 8. This is 24. This should be 17 more than 7. So go, 24 - 17. And whaddya know - it's 7!

4 0

2 years ago

PLEASE HELP PICTURE SHOWN

den301095 [7]

Option C and D is correct .....

4 0

3 years ago

The mean number of words per minute (WPM) read by sixth graders is 8888 with a standard deviation of 1414 WPM. If 137137 sixth g

Bingel [31]

Noticing that there is a pattern of repetition in the question (the numbers are repeated twice), we are assuming that the mean number of words per minute is 88, the standard deviation is of 14 WPM, as well as the number of sixth graders is 137, and that there is a need to estimate the probability that the sample mean would be greater than 89.87.

Answer:

"The probability that the sample mean would be greater than 89.87 WPM" is about $\\ P(z>1.56) = 0.0594$ .

Step-by-step explanation:

This is a problem of the distribution of sample means. Roughly speaking, we have the probability distribution of samples obtained from the same population. Each sample mean is an estimation of the population mean, and we know that this distribution behaves normally for samples sizes equal or greater than 30 $\\ n \geq 30$ . Mathematically

$\\ \overline{X} \sim N(\mu, \frac{\sigma}{\sqrt{n}})$ [1]

In words, the latter distribution has a mean that equals the population mean, and a standard deviation that also equals the population standard deviation divided by the square root of the sample size.

Moreover, we know that the variable Z follows a normal standard distribution, i.e., a normal distribution that has a population mean $\\ \mu = 0$ and a population standard deviation $\\ \sigma = 1$ .

$\\ Z = \frac{\overline{X} - \mu}{\frac{\sigma}{\sqrt{n}}}$ [2]

From the question, we know that

The population mean is $\\ \mu = 88$ WPM
The population standard deviation is $\\ \sigma = 14$ WPM

We also know the size of the sample for this case: $\\ n = 137$ sixth graders.

We need to estimate the probability that a sample mean being greater than $\\ \overline{X} = 89.87$ WPM in the distribution of sample means. We can use the formula [2] to find this question.

The probability that the sample mean would be greater than 89.87 WPM

$\\ Z = \frac{\overline{X} - \mu}{\frac{\sigma}{\sqrt{n}}}$

$\\ Z = \frac{89.87 - 88}{\frac{14}{\sqrt{137}}}$

$\\ Z = \frac{1.87}{\frac{14}{\sqrt{137}}}$

$\\ Z = 1.5634 \approx 1.56$

This is a standardized value and it tells us that the sample with mean 89.87 is 1.56 standard deviations above the mean of the sampling distribution.

We can consult the probability of P(z<1.56) in any cumulative standard normal table available in Statistics books or on the Internet. Of course, this probability is the same that $\\ P(\overline{X} < 89.87)$ . Then