Which is the most appropriate to describe a quantity decreasing at a steady rate

You open a drink stand where you sell coffee and hot chocolate. You sell coffee for $1.80 and hot chocolate for $3.15. At the en

Usimov [2.4K]

Answer:

c = 69 and h = 51

Step-by-step explanation:

You will need two different equations here

use variable c as coffee and variable h as hot chocolate

c + h = 120

1.80c + 3.15h = 284.40

By moving variables, you can alter the first equation

h = 120 - c

Now insert this into the second equation

1.80c + 3.15(120 - c) = 284.40

Multiply

1.80c + 378 - 3.15c = 284.40

Subtract the c

-1.35c + 378 = 284.40

Subtract 378 from both sides

-1.35c = -93.6

Divide both sides by -1.35

c = 69

Then plug into the first equation

69 + h = 120

Subtract 69

h = 51

7 0

2 years ago

Question 3

USPshnik [31]

Answer: The area of a sector is a fraction of the area of the circle. The fraction is equal to the ratio of the measure of the sector’s central angle to one full rotation, or 360°.

Step-by-step explanation:

3 0

2 years ago

What is the answer ?

mina [271]

Answer:

1)x=15

2)x=38

3)x=7

4)x=10

Step-by-step explanation:

3 0

2 years ago

Test scores of the student in a school are normally distributed mean 85 standard deviation 3 points. What's the probability that

Mrrafil [7]

Answer:

The probability that a random selected student score is greater than 76 is $\\ P(x>76) = 0.99865$ .

Step-by-step explanation:

The Normally distributed data are described by the normal distribution. This distribution is determined by two parameters, the population mean $\\ \mu$ and the population standard deviation $\\ \sigma$ .

To determine probabilities for the normal distribution, we can use the standard normal distribution, whose parameters' values are $\\ \mu = 0$ and $\\ \sigma = 1$ . However, we need to "transform" the raw score, in this case x = 76, to a z-score. To achieve this we use the next formula:

$\\ z = \frac{x - \mu}{\sigma}$ [1]

And for the latter, we have all the required information to obtain z. With this, we obtain a value that represent the distance from the population mean in standard deviations units.

<h3>The probability that a randomly selected student score is greater than 76</h3>

To obtain this probability, we can proceed as follows:

First: obtain the z-score for the raw score x = 76.

We know that:

$\\ \mu = 85$

$\\ \sigma = 3$

$\\ x = 76$

From equation [1], we have:

$\\ z = \frac{76 - 85}{3}$

Then

$\\ z = \frac{-9}{3}$

$\\ z = -3$

Second: Interpretation of the previous result.

In this case, the value is three (3) standard deviations below the population mean. In other words, the standard value for x = 76 is z = -3. So, we need to find P(x>76) or P(x>-3).

With this value of $\\ z = -3$ , we can obtain this probability consulting the cumulative standard normal distribution, available in any Statistics book or on the internet.

Third: Determination of the probability P(x>76) or P(x>-3).

Most of the time, the values for the cumulative standard normal distribution are for positive values of z. Fortunately, since the normal distributions are symmetrical, we can find the probability of a negative z having into account that (for this case):

$\\ P(z>-3) = 1 - P(z>3) = P(z$

Then

Consulting a cumulative standard normal table, we have that the cumulative probability for a value below than three (3) standard deviations is:

$\\ P(z$

Thus, "the probability that a random selected student score is greater than 76" for this case (that is, $\\ \mu = 85$ and $\\ \sigma = 3$ ) is $\\ P(x>76) = P(z>-3) = P(z$ .