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3 years ago

Answer all this for a lot of points

Mathematics

2 answers:

Aleksandr [31]3 years ago

7 0

Answer:

3. a. 1/4 b. 3/13

4. a. 4/9 b. 2/3

5. a. 3/8 b. 2/11

6. a. 1/4 b. 9/13

7. a. 3/11 b. 6/19

8. a. 1/9 b. 2/11

can I also get Brainliest???

Andreyy893 years ago

5 0

Answer:

3a =1/4

3b = 3/13

4a = 4/9

4b = 2/3

5a = 3/8

5b = 3/11

6a = 1/4

6b = 9/13

7a = 3/11

7b = 6/19

8a = 1/9

8b = 2/11

Step-by-step explanation:

Either divide by 2 or any of the factors of both the numbers

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7. A shopkeeper buys 300 identical articles a tota

sashaice [31]

Step-by-step explanation and answers:

300 articles at a total cost of $1500:

$1500 / 300 = $5 / article

Sells 260 articles at a price 20% above this ^ price:

20% of $5 is $1, so $5 + $1 = $6

Then he sells 260 articles at the price of ^ $6

260 * $6 = $1560

Each of the remaining articles is sold at a price that's 50% of the 260 he sold.

He sold those for $6, so he would now sell the last 40 for $3

From the remaining 40 articles, he makes 40 * $3, or $120

The shopkeeper made $1560 + $120 = $1680, which is $180 more than he bought them for ($1500)

Therefore, he made a profit percentage of $180 / $1500, (the amount of profit over the amount spent).

He made a profit percentage, compared to the cost price, of 12%.

3 0

3 years ago

a professor needs 2025 sheets of paper to print his classroom materials.Paper comes in packs of sheets.How many pack will the pr

Leto [7]

He would need to buy 4 packs of paper to print all of the material.

8 0

3 years ago

The formula to find the volume of a any pyramid is:

evablogger [386]

Answer:

V = A(h/3)

Step-by-step explanation:

6 0

3 years ago

Please help me!!!!!!!!

ValentinkaMS [17]

<u>Answer</u>

A) 7.3 in.

Explanation

The area of a triangle = 1/2 ×base length × height

In the question given, base length = height = x

Area = 27 in²

1/2 × x × x =27

1/2×x²=27

x² = 54

x = √54

= 7.3485 in²

4 0

3 years ago

The national mean annual salary for a school administrator is $90,00 a year (The Cincinnati Enquirer, April 7, 2012). A school o

timurjin [86]

Answer:

a) Null hypothesis: $\mu = 90000$

Alternative hypothesis: $\mu \neq 90000$

b) $p_v =2*P(t_{(24)}$

c) If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean for the salary differs from 9000 at 5% of significance.

Step-by-step explanation:

1) Data given and notation

77600 ,76000 ,90700 ,97200 ,90700 ,101800 ,78700 ,81300 ,84200 ,97600 ,

77500 ,75700 ,89400 ,84300 ,78700 ,84600 ,87700 ,103400 ,83800 ,101300

94700 ,69200 ,95400 ,61500 ,68800

We can calculate the sample mean and deviation with the following formulas:

$\bar X =\frac{\sum_{i=1}^n X_i}{n}$

$s=\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

The values obtained are:

$\bar X=85272$ represent the mean annual salary for the sample

$s=11039.23$ represent the sample standard deviation for the sample

$n=25$ sample size

$\mu_o =90000$ represent the value that we want to test

$\alpha=0.05$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

Part a: State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean salary differs from 90000, the system of hypothesis would be:

Null hypothesis: $\mu = 90000$

Alternative hypothesis: $\mu \neq 90000$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Part b: Calculate the statistic

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

$t=\frac{85272-90000}{\frac{11039.23}{\sqrt{25}}}=-2.141$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=25-1=24$

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

$p_v =2*P(t_{(24)}$

Part c: Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean for the salary differs from 9000 at 5% of significance.

6 0

3 years ago