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GREYUIT [131]
3 years ago
11

Solve the system using the elimination method. x+y−2z=5 −x+2y+z=2 2x+3y−z=9

Mathematics
1 answer:
Svetlanka [38]3 years ago
3 0
(1,2,-1) is the answer i got. 
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In a restaurant, the proportion of people who order coffee with their dinner is p. A simple random sample of 144 patrons of the
mote1985 [20]
<h2>Answer with explanation:</h2>

Given : In a restaurant, the proportion of people who order coffee with their dinner is p.

Sample size : n= 144

x= 120

\hat{p}=\dfrac{x}{n}=\dfrac{120}{144}=0.83333333\approx0.8333

The null and the alternative hypotheses if you want to test if p is greater than or equal to 0.85 will be :-

Null hypothesis : H_0: p\geq0.85   [ it takes equality (=, ≤, ≥) ]

Alternative hypothesis : H_1: p  [its exactly opposite of null hypothesis]

∵Alternative hypothesis is left tailed, so the test is a left tailed test.

Test statistic : z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}

z=\dfrac{0.83-0.85}{\sqrt{\dfrac{0.85(1-0.85)}{144}}}\\\\=-0.561232257678\approx-0.56

Using z-vale table ,

Critical value for 0.05 significance ( left-tailed test)=-1.645

Since the calculated value of test statistic is greater than the critical value , so we failed to reject the null hypothesis.

Conclusion : We have enough evidence to support the claim that p is greater than or equal to 0.85.

8 0
3 years ago
A student has a 2% salt water solution and a 7% salt water solution. To best imitate salt water at a local beach, he needs 1 lit
FromTheMoon [43]

Let

x-------> the amount of 2\% solution

y--------> the amount of 7\% solution

we know that

2\%=0.02\\7\%=0.07\\3.5\%=0.035

so

x+y=1

y=1-x -------> equation A

0.02x+0.07y=0.035 -------> equation B

substitute equation A in equation B

0.02x+0.07(1-x)=0.035

0.02x+0.07-0.07x=0.035

0.05x=0.035

x=0.7\ liters

find the value of y

y=1-x

y=1-0.7=0.3\ liters

therefore

The student need 0.7\ liters of 2\% solution and 0.3\ liters of 7\% solution

<u>the answer is</u>

A) The percent values were written incorrectly in the equation

B) The amount of 7% solution should be written as 1 – x, not x – 1.

8 0
3 years ago
Read 2 more answers
What is the value of P(9.1)? What does it tell us about the side length and perimeter
nadya68 [22]

Answer:

the answer is 36.4

Step-by-step explanation:

you have to multiply it by 4 so it it will look like this 9.1*4=36.4

4 0
3 years ago
Help please!!!!!!!!!!!
andreev551 [17]

Answer:

download a app called photo math

Step-by-step explanation:

Thank me later

3 0
3 years ago
Item 1
AleksandrR [38]

It took them 4 days to install 480 chairs which means if they were working at a constant rate they got 120 chairs installed daily. with 360 chairs left that means in 3 days they will finish. so overall, it took the workers 7 days to finish, or a week.

8 0
3 years ago
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