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3 years ago

-7x= -56 Is the answer A or B

Mathematics

1 answer:

FromTheMoon [43]3 years ago

6 0

Your answer choices are cut off. It appears that choice B isn't shown. However, if

-7x = -56

then

x = 8

the result is positive due to the fact that dividing two negatives (-56 over -7) leads to a positive result. As a check, replace x with 8 to get...

-7x = -56
-7*x = -56
-7*8 = -56
-56 = -56

the fact that we get the same value on both sides confirms we have the right answer.

You might be interested in

) To estimate weight of a certain product, 100 of these products are measured. The average weight and standard deviation are cal

inessss [21]

Answer:

a) $P(X$

And we can find this probability with the normal standard table or excel and we got:

$P(z$

And we would expect about 0.02275*10000 =227.5 rejected and 2.75 in the sample of 100 selected

b) $P(39$

And we can find this probability with this difference:

$P(-1$

And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.

$P(-1$

And we expect about 0.819*10000= 8190 and 81.9 in the sample od 100 selected

c) $40-1.64\frac{1}{\sqrt{100}}=39.836$

$40+1.64\frac{1}{\sqrt{100}}=40.164$

So on this case the 90% confidence interval would be given by (39.836;40.164)

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Part a

Let X the random variable that represent the weights of a population, and for this case we know the distribution for X is given by:

$X \sim N(40,1)$

Where $\mu=40$ and $\sigma=1$

We are interested on this probability

$P(X$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X$

And we can find this probability with the normal standard table or excel and we got:

$P(z$

And we would expect about 0.02275*10000 =227.5 rejected and 2.75 in the sample of 100 selected

Part b

$P(39$

And we can find this probability with this difference:

$P(-1$

And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.

$P(-1$

And we expect about 0.819*10000= 8190 and 81.9 in the sample od 100 selected

Part c

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$40-1.64\frac{1}{\sqrt{100}}=39.836$

$40+1.64\frac{1}{\sqrt{100}}=40.164$

So on this case the 90% confidence interval would be given by (39.836;40.164)

5 0

3 years ago

Fred's Fruit Stand has 252 pounds of fruit and sells 2 7/8 pounds per hour. Gary's grocery Store has 285 pounds of fruit and sel

enot [183]

Answer:

72.1 hours

Step-by-step explanation:

Let the number of hours be represented as: x

Fred's Fruit Stand has 252 pounds of fruit and sells 2 7/8 pounds per hour.

Convert 2 7/8 pounds to decimal = 2.875pounds

Hence:

252 - 2.875x

Gary's grocery Store has 285 pounds of fruit and sells 3 1/3 pounds per hour.

Convert 3 1/3 pounds to decimal = 3.333 pounds

Hence:

285 - 3.333x

How many hours until they have the same amount of fruit left?

This calculated by equating both equation together

252 - 2.875x = 285 - 3.333x

Collect like terms

-2.875x + 3.333x = 285 - 252

0.458x = 33

x = 33 / 0.458

x = 72.052401747 hours

x ≈ 72.1 hours

They would have the same amount of fruit left after 72.1 hours

6 0

3 years ago

(-2,0) And (a,3) <br> Slope 3 Over 8

choli [55]

Answer:

What is the Q.?

Step-by-step explanation:

8 0

3 years ago

In money in a savings account earned 8.5% intrest per annum, how much interest would be earned on $200.00 over two years?

Reil [10]

Answer:

$1305.91

Step-by-step explanation:

To solve this, we can use the geometric sequence formula

$\alpha _n=a_1*r^n^-^1$

If we plug in our values we get $\alpha _n=200*1.085^2^3$

Thus, leaving us with 1305.91

Hope this helps

5 0

3 years ago

7(x – 3) – 5(2x - 4) = 5

WITCHER [35]

Answer:

-2

Step-by-step explanation:

7x-21-10x+20=5

7x-10x-1=5

-3x=5+1

x=-6/3

x=-2

7 0

4 years ago

Read 2 more answers