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dusya [7]
4 years ago
5

A 21 foot beam is to be cut into three pieces so that the second and the third piece are each 3 times the length of the first pi

ece if x represents the length of the shorter piece, find the lengths of all three pieces
Mathematics
1 answer:
mylen [45]4 years ago
6 0

x+3x+3x=21

7x=21

x=3

3, 9, 9=21

the answers are 3, 9, and 9

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What is the answer to -3(1+6r)=14-r
Ilia_Sergeevich [38]
<span>-3(1+6r)=14-r
-3 - 18r = 14 - r ...expand by using distributive property
-3 -17r = 14 ...add (r) to both sides
-17r = 17 ...add (3) to both sides
     r = -1 ....divide both sides by (-17)</span>
5 0
3 years ago
Read 2 more answers
Which polynomial is prime?<br><br> x2 – 36<br> x2 + 16<br> x2 – 7x + 12<br> x2 – x – 20
juin [17]

Answer:

x2 - 7x + 12

Step-by-step explanation:

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3 0
3 years ago
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The mean annual premium for automobile insurance in the United States is $1503 (Insure website, March 6, 2014). Being from Penns
romanna [79]

Answer:

If we compare the p value and the significance level for example \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can conclude that the mean annual premium in Pennsylvania is significantly lower than the national mean annual premium of 1503 at 5% of significance.

Step-by-step explanation:

1) Data given and notation  

\bar X=1440 represent the mean annual premium value for the sample  

s=165 represent the sample standard deviation for the sample  

n=25 sample size  

\mu_o =1503 represent the value that we want to test

\alpha represent the significance level for the hypothesis test.  

t 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 annual premium in Pennsylvania is lower than the national mean annual premium, the system of hypothesis would be:  

Null hypothesis:\mu \geq 1503  

Alternative hypothesis:\mu < 1503  

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:  

t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}  (1)  

t-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:  

t=\frac{1440-1503}{\frac{165}{\sqrt{25}}}=-1.909    

P-value

The first step is calculate the degrees of freedom, on this case:  

df=n-1=25-1=24  

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

p_v =P(t_{(24)}  

Conclusion  

If we compare the p value and the significance level for example \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can conclude that the mean annual premium in Pennsylvania is significantly lower than the national mean annual premium of 1503 at 5% of significance.  

7 0
3 years ago
Help I don't understand this math. Whoever gets the right answer gets Brainlist! :)​
Jlenok [28]

Answer:

1200 more beats in 3 seconds or

400 more beats in 1 second

Step-by-step explanation:

A Mosquito beats its wings at a rate of 600 times per second.

A honey bee beats its wings at a rate of 200 times per second.

600 - 200 = 400

The mosquito beats 400 more times per second

400 X 3 = 1200

5 0
2 years ago
A rectangular plot of ground is 30 meters longer than it is wide. its area is 10,000 square meters.
dimulka [17.4K]
A = W· L
10,000 = W ( W +30 ) = W² + 30 W
W² + 30 W - 10,000 = 0
W = \frac{-30+ \sqrt{900+40000} }{2}=  \frac{-30+202.24}{2} = 86.12
L = 86.12 + 30 = 116.12
Width of a plot is 86.12 m and lenght is 116.12 m.
Check : A = 116.12 · 86.12 ≈ 10,000
6 0
3 years ago
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