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miv72 [106K]
3 years ago
6

15. The sum of two numbers is 8. The difference of the two numbers is 2.

Mathematics
1 answer:
matrenka [14]3 years ago
5 0

Answer:

3 AND 5

Step-by-step explanation:

LET THE TWO NUMBERS BE X AND Y

THEN

X + Y = 8 …….1

X – Y = 2 …… 2

WE SOLVE SIMULTANOUSLY  

SUBTRACTNG EQATION 2 FROM 1

X – X  + Y – (-Y) = 8 – 2

Y + Y = 6

2Y = 6

DIVIDING EACH TERM BY 2

2Y/2 = 6/2

Y = 3

THEN PUTTING Y = 3 IN EQUATION 1

X + 3 = 8

X = 8 – 3

X = 5

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His mistake was in multiplying the 3 with the 12. He should have divided it from the 12 because that would have gotten rid of the 3 with the variable. It would also lead to the correct answer, which is b=4
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Which graph shows a system of equations with no solutions? On a coordinate plane, the graphs of 2 circles are shown. Both circle
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Answer:

1st Graph: 2 circles are shown

Step-by-step explanation:

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Read 2 more answers
A student in wildlife management studied trout habitat in the upper Shavers Fork watershed in West Virginia. The springtime wate
nataly862011 [7]

Answer:

C. H 0 : μ = 7 vs. Ha : μ ≠ 7

Since the calculated value of t = -9.462 falls in the critical region  t ≤-2.048

We conclude that the  springtime water the tributary water basin around the Shavers Fork watershed is not neutral. We accept our alternate hypothesis and reject the null hypothesis.

Step-by-step explanation:

The null hypothesis the usually the test to be performed. Here we want to check whether the water is neutral or not. Neutral water must have a pH of 7 . This can be stated as the null hypothesis. And the claim is treated as the alternate hypothesis that water in not neutral or not having pH= 7

In symbols it will be written as

H0: : μ = 7 vs. Ha : μ ≠ 7

So choice C is the best option for this hypothesis testing.

Let the significance level be 0.05

The degrees of freedom = n-1= 29-1 = 28

The critical value is  t ≥ 2.048 and t ≤ - 2.048 for 0.05 two tailed test with 28 df.

The test statistic to use is t- test

t= x- u/ s/√n

The total sum is 170.9 and mean = x= 5.893

The u = 7

And the sample standard deviation is =s= 0.63

Putting the values

t= 5.893-7/0.63/√29

t= - 1.107/0.11699

t= -9.4623

Since the calculated value of t = -9.462 falls in the critical region  t ≤-2.048

We conclude that the  springtime water the tributary water basin around the Shavers Fork watershed is not neutral. We accept our alternate hypothesis and reject the null hypothesis.

4 0
3 years ago
A civil engineer is analyzing the compressive strength of concrete. Compressive strength is normally distributed with A random s
wel

Answer:

95%: (3278.354 ; 3270.083)

99% : (3221.646 ; 3278.354)

Step-by-step explanation:

Given :

Sample size, n = 12

Mean, xbar = 3250

Sample standard deviation = √1000

The 95% confidence interval :

Mean ± Margin of error

Margin of Error = Tcritical * s/√n

Tcritical at 0.05, df=12-1 = 11 ;

Tcritical at 95% = 2.20

Hence,

Margin of Error = (2.20 * √1000/√12) = 20.083

Confidence interval : 3250 ± 20.083

Lower boundary = 3250 - 20.083 = 3229.917

Upper boundary = 3250 + 20.083 = 3270.083

2.)

The 99% confidence interval :

Mean ± Margin of error

Margin of Error = Tcritical * s/√n

Tcritical at 0.01, df=12-1 = 11 ;

Tcritical at 99% = 3.106

Hence,

Margin of Error = (3.106 * √1000/√12) = 28.354

Confidence interval : 3250 ± 28.354

Lower boundary = 3250 - 28.354 = 3221.646

Upper boundary = 3250 + 28.354 = 3278.354

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3 years ago
What’s 2 +2x7x8+3x78=?
Xelga [282]

Answer:348

Step-by-step explanation:

6 0
3 years ago
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