A number c minus 12 is greater than 4.

Write 5/9 , 3/7 , 2/3 in order from least to greatest.

Kamila [148]

Answer:

2/3,3/7,5/9.

Step-by-step explanation:

I'm sure it's the right answer

6 0

3 years ago

3 + 2 x 7 - 30(^2)<br><br> help me

shepuryov [24]

There is no solution to this problem. Why? Well, see below for an explanation!

We can initially solve this problem using PEMDAS. Where we go wrong will be identified later. The P stands for Parenthesis, but there are none in this equation so we can skip that step. Next is E, which stands for Exponents. We do have an exponent, but it is separate from the problem. That would deem the problem invalid to solve because there is no base number for the exponent to be solved. Disregarding the exponent, we can solve by using M, which means Multiplication.

2 x 7 = 14

Next step, we can simplify to make the equation a tad bit neater.

3 + 14 - 30

Next up is D, meaning we need to divide. There are no numbers to divide though, so this step can be skipped.

Next step would be A, meaning we need to add.
3 + 14 = 17

Next step, we can simplify to make the equation neater as stated above.

17 - 30

17 - 30 = -13.

Disregarding the exponent, your answer would be -13. Including the exponent, however, would make the equation irrelevant. If you need extra help understanding this, let me know and I will gladly assist you.

3 0

3 years ago

23. A certain type of gasoline is supposed to have a mean octane rating of at least 90. Suppose measurements are taken on of 5 r

Nostrana [21]

Answer:

a) $p_v =P(Z$

b) Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

c) $P(\bar X >90)=1-P(Z$

$1-P(Z$

d) For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

Step-by-step explanation:

Previous concepts and data given

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".

We can calculate the sample mean and deviation with the following formulas:

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

$s=\sqrt{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$\bar X=88.96$ represent the sample mean

$s=1.011$ represent the sample standard deviation

n=5 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is less than 90, the system of hypothesis would be:

Null hypothesis: $\mu \geq 90$

Alternative hypothesis: $\mu < 90$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{88.96-90}{\frac{0.8}{\sqrt{5}}}=-2.907$

Part a

P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=5-1 = 4$

Then since is a left tailed test the p value would be:

$p_v =P(Z$

Part b

Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

Part c

We want this probability:

$P(\bar X$

The best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}$

If we apply this formula to our probability we got this:

$P(\bar X >90)=1-P(Z$

$1-P(Z$

Part d

For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

7 0

3 years ago

Michelle is two years older than her sister Nicole. 10 years ago, Michelle was twice as old as her sister. How old is Michelle n

BaLLatris [955]

Answer:

Michelle is 14 years old.

Step-by-step explanation:

The only logical explanation for the two being two years apart in age and Michelle being twice as old ten years ago is if Michelle was 4 years old and Nicole was 2 years old ten years ago. To verify this, we can use a System of equations.

Let:
N = Nicole's Age

M = Michelle's Age

N + 2 = M

2n-10 = M

Since both equal Michelle's age, we can make a two step equation out of it.

N + 2 = 2n - 10

2 = N - 10

12 = N

We've found Nicole's age, allowing us to plug the answer back into the variable to get Michelle's.

12 + 2 = 14

7 0

3 years ago

Read 2 more answers

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jolli1 [7]

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6 0

3 years ago

A number c minus 12 is greater than 4.​

A number c minus 12 is greater than 4.