Suzie purchased a dress on sale for $27.20. This is 85% of the original price. What was the original price?

What should be done to both sides of the equation in order to solve y - 4.5 = 12.2?

maw [93]

Y - 4.5 = 12.2

your solving for y which means your trying to get rid of 4.5 so that y can equal something. The opposite of -4.5 would be +4.5, so you would add 4.5 to both sides to get

y = 16.7

So your answer would be

A. Add 4.5

and also dont' say your stupid because all you need is a little explanation and you'll get it, its very easy you just need to take the time to practice :-)

6 0

3 years ago

Which expression represents: twice a number increased by 39

Cerrena [4.2K]

Answer:

2x+39

Step-by-step explanation:

8 0

3 years ago

Sulfur compounds cause "off-odors" in wine, so winemakers want to know the odor threshold, the lowest concentration of a compoun

aev [14]

Answer:

a) $29.4-1.96\frac{7}{\sqrt{10}}=25.06$

$29.4+1.96\frac{7}{\sqrt{10}}=33.74$

So on this case the 95% confidence interval would be given by (25.06;33.74)

b) $z=\frac{29,4-25}{\frac{7}{\sqrt{10}}}=1.988$

$p_v =P(z>1.988)=0.0234$

If we compare the p value and the significance level given $\alpha=Step-by-step explanation:Previous conceptsA confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval". 
The margin of error is the range of values below and above the sample statistic in a confidence interval. 
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean". 
Part a
Data given: 30 30 42 35 22 33 31 29 19 23
We can calculate the sample mean with the following formula:[tex] \bar X = \frac{\sum_{i=1}^n X_i}{n}= 29.4$ the sample mean

$\mu$ population mean (variable of interest)

$\sigma=7$ represent the population standard deviation

n=10 represent the sample size

95% confidence interval

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

Now we have everything in order to replace into formula (1):

$29.4-1.96\frac{7}{\sqrt{10}}=25.06$

$29.4+1.96\frac{7}{\sqrt{10}}=33.74$

So on this case the 95% confidence interval would be given by (25.06;33.74)

Part b

What are H0 and Ha for this study?

Null hypothesis: $\mu \leq 25$

Alternative hypothesis : $\mu>25$

Compute the test statistic

The statistic for this case 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".

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

$z=\frac{29,4-25}{\frac{7}{\sqrt{10}}}=1.988$

Give the appropriate conclusion for the test

Since is a one side right tailed test the p value would be:

$p_v =P(z>1.988)=0.0234$

Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

8 0

3 years ago

Proportions - if 1 subscription costs $21, how much is 28 subscriptions?

Len [333]

1 subscription = $21
28 subscriptions = x
You know 1 subscription is $21
You want to find out how much 28 subscriptions are
Multiply 28 (subscriptions) by 21 ($ per subscription)
28 x 21 = 588
28 subscriptions cost $588
If you would like the formula to find out how many subscriptions cost hat amount of money,
21x = y
x is how many subscriptions you want, while y is the total cost of the money

6 0

3 years ago

He slope-intercept form of the equation of a line that passes through point (-3, 8) is y = -x + 6. What is the point-stopetom

Shkiper50 [21]

y-3=2(x+)Step-by-step explanation:

5 0

3 years ago