I am so glad people help me on brainlyy. i still need help with this question tho

During Christmas a book store sold 30 books. If the ratio of books go bookmarks sold was 10:1 ,how many bookmarks did the store

Snowcat [4.5K]

<span>books to bookmarks
books : bookmarks
10 : 1
10 * 3 : 1 * 3
30 : 3
3 bookmarks

Since the book store sold 30 books they also sold 3 bookmarks.

Answer: 3 bookmarks</span>

7 0

3 years ago

In 10 and 11, find the area in square units of each polygon.

alexandr1967 [171]

Answer:

10: 12 units^2 11: 33 units^2

Step-by-step explanation:

10:

Divide into square and 2 triangles (for simplicity)

square=9

one triangle=3/2

both triangles combined=3

9+3=12

11:

divide into 2 triangles

top triangle: height= 4, base=6

bottom triangle: height= 7, base=6

top=12

bottom=21

Add, 33.

7 0

2 years ago

Read 2 more answers

PLSSS HELLLPPP MEE!!

MArishka [77]

Answer:

the answer is 8

3 0

3 years ago

It is known that IQ scores form a normal distribution with a mean of 100 and a standard deviation of 15. If a researcher obtains

sdas [7]

Answer:

$X \sim N(100,15)$

Where $\mu=100$ and $\sigma=15$

We select a sample of n=16 and we are interested on the distribution of $\bar X$ , since the distribution for X is normal then we can conclude that the distribution for $\bar X$ is also normal and given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

Because by definition:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$E(\bar X) = \mu$

$Var(\bar X) = \frac{\sigma^2}{n}$

And for this case we have this:

$\mu_{\bar X}= \mu = 100$

$\sigma_{\bar X} = \frac{15}{\sqrt{16}}= 3.75$

Step-by-step explanation:

Previous concepts

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 Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the IQ scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(100,15)$

Where $\mu=100$ and $\sigma=15$

We select a sample of n=16 and we are interested on the distribution of $\bar X$ , since the distribution for X is normal then we can conclude that the distribution for $\bar X$ is also normal and given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

Because by definition:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$E(\bar X) = \mu$

$Var(\bar X) = \frac{\sigma^2}{n}$

And for this case we have this:

$\mu_{\bar X}= \mu = 100$

$\sigma_{\bar X} = \frac{15}{\sqrt{16}}= 3.75$

6 0

3 years ago

How do i find scale factor?

Kazeer [188]

To find scale factor you first must find two corresponding sides. then divide one by the other. note that if you divide the smaller side by the larger you will get a number less that one and if you divide the larger side by the smaller side you will get a number greater than one.

6 0

4 years ago