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3 years ago

18 is 45% of what numbet

2 answers:

8 0

18 is 45% of a number
18 is 45% of x
18 = 45% of x
18 = 0.45 * x

Now, to isolate x, you divide both sides of the equation by 0.45.

18 / 0.45 = 0.45*x /0.45
x = 40

So, 18 is 45% of 40. Hope this helps! :)

Nataly [62]3 years ago

4 0

Part/Whole=Percent/100
Part=18
Percent=45
Whole= a variable that we are trying to figure out
so now its 18/x=45/100
Cross multiply and get
45x=1800
Divide by 45 and get 40. 18 is 45%of 40

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Suppose the standard deviation of a normal population is known to be 3, and H0 asserts that the mean is equal to 12. A random sa

blagie [28]

Answer:

$z=\frac{12.95-12}{\frac{3}{\sqrt{36}}}=1.9$

$p_v =P(z>1.9)=0.0287$

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, so we can conclude that the true mean is higher than 12 at 5% of signficance.

Step-by-step explanation:

Data given and notation

$\bar X=12.95$ represent the sample mean

$\sigma=3$ represent the population standard deviation for the sample

$n=36$ sample size

$\mu_o =12$ represent the value that we want to test

$\alpha=0.05$ represent the significance level for the hypothesis test.

z would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is equal to 12, the system of hypothesis would be:

Null hypothesis: $\mu \leq 12$

Alternative hypothesis: $\mu > 12$

Since we know the population deviation, is better apply a z 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:

$z=\frac{12.95-12}{\frac{3}{\sqrt{36}}}=1.9$

P-value

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

$p_v =P(z>1.9)=0.0287$

Conclusion

4 0

3 years ago

Read 2 more answers

A rectangle has a length of (x+10) centimeters and a width of x centimeters. If the perimeter is 32 centimeters, what is the len

I am Lyosha [343]

Given:

Length of rectangle = (x+10) cm

Width of the rectangle = x cm

Perimeter = 32 cm

To find:

The length of the rectangle.

Solution:

We know that,

$Perimeter=2(l+w)$

Where, l is length and w is width.

Substituting the values, we get

$32=2((x+10)+x)$

$32=2(2x+10)$

$32=4x+20$

Subtract 20 from both sides.

$32-20=4x$

$12=4x$

Divide both sides by

$3=x$

So, the length is

$3+10=13$

Therefore, the length of the rectangle is 13 cm.

7 0

3 years ago

What is G if B = A × (1+G)T and B = 3,455, A = 1,969, and T = 8? Answer as a rate in decimal format so that 12.34% would be ente

zubka84 [21]

Answer:

G=0.0728

Step-by-step explanation:

The expression given is:

$B=A*(1+G)^T$

This expression has the format of a compounded interest at a rate G for a time T. If B = 3,455, A = 1,969, and T = 8, the value of the rate G is determined by:

$3,455=1,969*(1+G)^8\\G = \sqrt[8]{\frac{3,455}{1,969}}-1\\G=0.0728$

The rate G is 0.0728.

7 0

3 years ago

What are the factors of 5x2 + 39x − 8?

prisoha [69]

Answer:

C. (5x - 1)(x + 8)

Step-by-step explanation:

In a factoring problem by hand, the common steps to solve would be the "AM" method, or (Add-Multiply). Simply stated, finding what adds to the x-coeficient and what multiplies to the constant. In this case, what adds to 39(x) and what multiplies to 8. Just reading that, we can see that there aren't any numbers that can do that, so we have to improvise. Set up the problem equal to something that it can factor into: