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Vera_Pavlovna [14]
3 years ago
11

DG's Plumbing and Heating charges $50 plus $65 per hour for emergency service. Bill was billed $440 for an emergency call. How l

ong was the plumber at Bill's house?
Mathematics
1 answer:
spin [16.1K]3 years ago
8 0
The plumber was at Bill's house for 6 hours
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6x-3x+9=2+8x<br><br> X+8=15+4x-7<br><br> 4x+5-x=10+3x+4
Effectus [21]
In order to find the solution you just have to answer one of the equations to solve for x then plug it in for the other ones. so lets start. so x equals 1/3
4 0
3 years ago
Number one and number two
Amanda [17]
1.  sum of exterior angles = 360 

so one interior angles = 180 - (360/30) = 180 - 12 = 168 degrees
sum of all the interior angles = 168*30 =  5040  
B


2.   H  

the sum of exterior angles of all polygons is 360 degrres

4 0
3 years ago
It’s asking for the area<br> Please help! Thank you!
Eddi Din [679]

Answer: x^2+9x+20

Step-by-step explanation:

To find the area you multiply the sides so it should be (x+4)(x+5) which is x^2+9x+20. Good luck!

6 0
3 years ago
Does anyone get this?
stepladder [879]

Answer: B

Step-by-step explanation:

 In the systems of equation it already gives you the solution for x  which is -2 so all you have to do is substitute -2 into the first equation and solve for y.

y= 2/3x + 3    

x= -2

Substitute x for -2

y = \frac{2}{3}* \frac{-2}1}  + 3  

y= \frac{-4}{3} + \frac{3}{1}    

y = \frac{5}{3}  

so now you have the solution like this (-2,\frac{5}{3})

8 0
3 years ago
At a local university, a sample of 49 evening students was selected in order to determine whether the average age of the evening
pav-90 [236]

Answer:

z=\frac{23-21}{\frac{3.5}{\sqrt{49}}}=4    

p_v =2*P(z>4)=0.0000633  

When we compare the significance level \alpha=0.1 we see that p_v so we can reject the null hypothesis at 10% of significance. So the  the true mean is difference from 21 at this significance level.

Step-by-step explanation:

Data given and notation  

\bar X=23 represent the sample mean

\sigma=3.5 represent the population standard deviation

n=49 sample size  

\mu_o =21 represent the value that we want to test

\alpha=0.1 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 average age of the evening students is significantly different from 21, the system of hypothesis would be:  

Null hypothesis:\mu = 21  

Alternative hypothesis:\mu \neq 21  

The statistic is given by:

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

Calculate the statistic

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

z=\frac{23-21}{\frac{3.5}{\sqrt{49}}}=4    

P-value

Since is a two sided test the p value would be:  

p_v =2*P(z>4)=0.0000633  

Conclusion  

When we compare the significance level \alpha=0.1 we see that p_v so we can reject the null hypothesis at 10% of significance. So the  the true mean is difference from 21 at this significance level.

8 0
3 years ago
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