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3 years ago

(1/2a - 1/3b) - (1/3b - 1/2a)

Mathematics

1 answer:

professor190 [17]3 years ago

7 0

Answer:

a- 2b/3

Step-by-step explanation:

1) Remove the parentheses and combine like terms

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The attendance at a family reunion was 160 people. This was 125% of last year's attendance. How many people attended the reunion

Alex787 [66]

If you would like to know how many people attended the reunion last year, you can calculate this using the following steps:

125% of last year's attendance is 160 people
125% of x is 160
125% * x = 160
125/100 * x = 160 /*100/125
x = 160 * 100 / 125
x = 128 people (last year)

Result: 128 people attended the reunion last year.

4 0

3 years ago

Suppose a 90% confidence interval for the mean salary of college graduates in a town in Mississippi is given by [$38,737, $50,46

JulsSmile [24]

Answer:

a. The point estimate was of $44,600.

b. The sample size was of 16.

Step-by-step explanation:

Confidence interval concepts:

A confidence interval has two bounds, a lower bound and an upper bound.

A confidence interval is symmetric, which means that the point estimate used is the mid point between these two bounds, that is, the mean of the two bounds.

The margin of error is the difference between the two bounds, divided by 2.

a. What is the point estimate of the mean salary for all college graduates in this town?

Mean of the bounds, so:

(38737+50463)/2 = 44600.

The point estimate was of $44,600.

b. Determine the sample size used for the analysis.

First we need to find the margin of error, so:

$M = \frac{50463-38737}{2} = 5863$

Relating the margin of error with the sample size:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.9}{2} = 0.05$

Now, we have to find z in the Z-table as such z has a p-value of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.05 = 0.95$ , so Z = 1.64.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

For this problem, we have that $\sigma = 14300, M = 5863$ . So

$M = z\frac{\sigma}{\sqrt{n}}$

$5863 = 1.645\frac{14300}{\sqrt{n}}$

$5863\sqrt{n} = 1.645*14300$

$\sqrt{n} = \frac{1.645*14300}{5863}$

$(\sqrt{n})^2 = (\frac{1.645*14300}{5863})^2$

$n = 16$

The sample size was of 16.

7 0

3 years ago

The diagram below represent the rate of making copies on a copy machine. Which table represent this rate?

Nuetrik [128]

Answer:

its B

Step-by-step explanation:

6 0

2 years ago

Zak has 3/5 pack of pencils. Of these, 2/7 are blue. How many blue pencils does Zak have?

Basile [38]

Answer:

11/35

Step-by-step explanation:

First, you would have to make a common denominator. To do this, multiply these 2 denominator, 5 and 7. You should get 35. Then, you would have to make the numerator equal to the denominator. In this case, multiply 3 to 7 and 2 to 5. Now you have 21/35 and 10/35. Now subtract 21 from 10, and simplify if needed. I hope this helps!

7 0

3 years ago

Read 2 more answers

Which expression is the factorization of x2 + 10x + 21?

LiRa [457]

<h2>Solution:</h2>

Equation: x² + 10x + 21

Step 1: Find two numbers that can add up to 10 and be multiplied to 21. We have: 7 & 3, in the sense that 7+3=10, and 7×3=21. Replacing 10 with 7+3, the equation is now → x² + 7x + 3x + 21

Step 2: Get the new equation bracketed → (x² + 7x) (+3x + 21)

Step 3: Use 'x' in the equation. For the first part, we have 'x'. x² = x × x so, bring out one x out side the bracket, divide 7x by = 7 → x (x +7). Do the same for the second part by dividing 21 by 3 = 7, and then bringing out 3 from the bracket → 3 (x + 7).

Bringing everything together, we have: x(x+7) +3(x+7) → (x+3) (x+7)

<h3>Final answer:</h3>

(x+3) (x+7)

<h3 />

4 0

2 years ago