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adoni [48]
3 years ago
13

How to subtractat a positive and negative rational number

Mathematics
1 answer:
Anna71 [15]3 years ago
5 0

Answer:

<em>75</em>

Step-by-step explanation:

Subtracting a number means adding the opposite.

The opposite of a number is the number you obtain by just changing the sign.

The opposite of 5 is -5. The opposite of 100 is -100. The opposite of -4.5 is 4.5. The opposite of 0 is 0. Zero is the only number that is equal to its opposite.

You need to subtract -45, so add the opposite of -45 which is 45.

30 - (-45) = 30 + 45 = 75

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The manager of a customer support center takes an SRS of 40 reported issues and finds that 22% of the sampled issues required mo
ki77a [65]

Answer:

The mean of the sampling distribution of p is 0.25 and the standard deviation is 0.0685.

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean \mu and standard deviation \sigma, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean \mu and standard deviation s = \frac{\sigma}{\sqrt{n}}.

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean \mu = p and standard deviation s = \sqrt{\frac{p(1-p)}{n}}

25% of the approximately 1000 issues reported per month that require more than one call.

This means that p = 0.25

What are the mean and standard deviation of the sampling distribution of p?

Sample of 40 means that n = 40.

By the Central Limit Theorem,

The mean is \mu = p = 0.25

The standard deviation is s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.25*0.75}{40}} = 0.0685

The mean of the sampling distribution of p is 0.25 and the standard deviation is 0.0685.

3 0
3 years ago
Someone please help me with this :3
andreyandreev [35.5K]

Answer:

2

Step-by-step explanation:

\dfrac{\frac{2}{3}}{\frac{1}{3}}=\frac{2}{3}\cdot \frac{3}{1}=\frac{6}{3}=2. Hope this helps!

5 0
4 years ago
Read 2 more answers
(NO LINKS) I BEG U HALP FELLOW SMART PPL
bazaltina [42]

Answer: See the image below for the filled out table.

The other root is x = -2

===========================================================

Explanation:

The turning point is at (1, -45) which is the vertex. This is where the graph goes downhill, and then turns around to go uphill, or vice versa. Depending on the direction, the vertex is the lowest point or the highest point on the parabola.

We have (h,k) = (1,-45) as the vertex, so h = 1 and k = -45

y = a(x-h)^2 + k

y = a(x-1)^2 + (-45)

y = a(x-1)^2 - 45

Now plug in any other point from the table. You cannot pick (1,-45) or else you won't be able to solve for the variable 'a'. Let's go for (0,-40)

We'll plug x = 0 and y = -40 into the equation above to solve for 'a'

y = a(x-1)^2 - 45

-40 = a(0-1)^2 - 45

-40 = a(-1)^2 - 45

-40 = a - 45

a-45 = -40

a = -40+45

a = 5

Therefore, the equation for this parabola is

y = 5(x-1)^2 - 45

As a way to check, we can plug in something like x = -3 to find that...

y = 5(x-1)^2 - 45

y = 5(-3-1)^2 - 45

y = 5(-4)^2 - 45

y = 5(16) - 45

y = 80 - 45

y = 35

Which matches what the table shows in the first column. I'll let you verify the other columns. As you can probably guess at this point, we'll plug in the x values to get the corresponding y values.

So for x = -2, we get...

y = 5(x-1)^2 - 45

y = 5(-2-1)^2 - 45

y = 5(-3)^2 - 45

y = 5(9) - 45

y = 45 - 45

y = 0

The result of 0 here indicates we have a root at x = -2. This is the other x intercept. The x intercept already given to us was x = 4.

The rest of the table is filled out using the same idea. You should get what you see below.

3 0
3 years ago
A classroom has 12 students with brown hair, 8 students with black hair, and 5 students with blonde hair. If three students are
aksik [14]
I am going to have to go with, C, because the other answers are Invalid.
4 0
3 years ago
The water level of a pond rises an inch every 16 days
Scilla [17]

Answer:

16 weeks

Step-by-step explanation:

7 inches rise

7x16days = 112 days

112 days / 7 days = 16 weeks

5 0
4 years ago
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