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3 years ago

The recommended angle for a firefighting ladder is 75°. When a 110-foot ladder

Mathematics

1 answer:

Licemer1 [7]3 years ago

3 0

Answer:106.38 feet

Step-by-step explanation:

This can be solved by using pythagoras theorem

c=110 feet

b=28 feet

a=?

a=sqrt(110^2-28^2)

=sqrt(12100-784)

=sqrt(11316)

=106.3766 feet

=106.38

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Measuring and arcs.

n200080 [17]

Answer:

Hope this helps

Step-by-step explanation:

3. Minor arc, 44°

4. Major arc, 140°

5. Minor arc, 44°

6. Major arc, 316°

7. Semi circle, 180°

8. Major arc, 140°

9. 38°

10. 52°

11. 142°

12. 128°

13. 232°

14. 308°

7 0

3 years ago

I need help on this one so please can someone help me with this thanks

BlackZzzverrR [31]

Answer:

the price of each cd is 13.45

Step-by-step explanation:

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3 years ago

Can you plsss help me due now

Bess [88]

Answer:

Step-by-step explanation:

I'll try to be brief

Let's plug in our 'y' variable (2x)

2x + (2x) = 20

4x = 20

x = 5

Now, plug in our 'x' variable to get our 'y' variable:

y = 2(5)

y = 10

So, our answer in (5, 10)

Or, D

5 0

1 year ago

Carol and Jan leave from the same place and travel on the same road going the same direction. Carol walks at a rate of 2 miles p

kramer

Let, the time when <span>Jan cough up to Carol = x

We know, Distance = Speed * Time.

So, Equation would be: 2x + 5*2 = 6x

2x + 10 = 6x

6x - 2x = 10

4x = 10

x = 10/4 = 2.5

Distance traveled in that time = 2.5 * 6 = 15 miles

In short, Your Answer would be: 15 miles

Hope this helps!</span>

7 0

4 years ago

23. A certain type of gasoline is supposed to have a mean octane rating of at least 90. Suppose measurements are taken on of 5 r

Nostrana [21]

Answer:

a) $p_v =P(Z$

b) Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

c) $P(\bar X >90)=1-P(Z$

$1-P(Z$

d) For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

Step-by-step explanation:

Previous concepts and data given

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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".

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

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

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

$\bar X=88.96$ represent the sample mean

$s=1.011$ represent the sample standard deviation

n=5 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is less than 90, the system of hypothesis would be:

Null hypothesis: $\mu \geq 90$

Alternative hypothesis: $\mu < 90$

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:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-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".

Calculate the statistic

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

$z=\frac{88.96-90}{\frac{0.8}{\sqrt{5}}}=-2.907$

Part a

P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=5-1 = 4$

Then since is a left tailed test the p value would be:

$p_v =P(Z$

Part b

Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

Part c

We want this probability:

$P(\bar X$

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

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

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

$P(\bar X >90)=1-P(Z$

$1-P(Z$

Part d

For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

7 0

3 years ago