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2 years ago

Find the missing length

Mathematics

2 answers:

pshichka [43]2 years ago

7 0

Answer:

9 yd

Step-by-step explanation:

15 yd - 6 yd = 9 yd

Please mark my answer as brainiest

Darya [45]2 years ago

7 0

Answer:

9 yd

Step-by-step explanation:

The top has a length of 15 yd

The bottom has a length of 6 +x

15 = 6+x

Subtract 6 from each side

15-6 = 6-6+x

9 = x

9 yds in the missing length

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Write an expression to describe the sequence below. Use n to represent the position of a term in the sequence, where n = 1 for t

Viefleur [7K]

Each term differs by -68 and the first term is -68, we have:

$a_{n}=a_1-68(n-1) \implies \\ a_{n}=a_1-68n+68 \implies\\ a_n=-68-68n+68 \implies \\ a_n=-68n$

As an expession it's just -68n.

6 0

3 years ago

Kelsey can buy 2 pounds of apples for 7$. Write an equation to represent the cost, c, for a, pounds of apples.

zmey [24]

$\huge\boxed{c=3.5a}$

First, we need to find how much a single pound of apples costs.

Do this by dividing.

$\frac{\$7}{2\ \text{lbs.}}\div\frac{2}{2}=\frac{\$(7\div 2)}{(2\div 2)\ \text{lbs.}} = \frac{\boxed{\$3.50}}{1\ \text{lb.}}$

Now, write an equation.

$\large\boxed{c=3.5a}$

This represents that the cost equals 3.5 times the number of apples.

8 0

3 years ago

Read 2 more answers

Nico wants to buy blinds for his window. The blinds are 140 cm wide. Will

RoseWind [281]

Answer:

No, the blinds will not fit inside a 45-inch space.

Step-by-step explanation:

No, the blinds will not fit inside a 45-inch space, because the blinds are too large.

To check;

140 cm = 56 inches

140 / 2.5 = 56

45 inches = 112.5 cm

45 x 2.5 = 112.5

Hope this helps!

5 0

2 years ago

Estimate the minimum and maximum ages for typical textbooks currently used in college courses, then use the range rule of thumb

Maksim231197 [3]

Answer:

$n=(\frac{1.64(4)}{0.25})^2 =688.537 \approx 689$

So the answer for this case would be n=689 rounded up to the nearest integer

Step-by-step explanation:

Assuming this complete question: "Suppose that the minimum and maximum ages for typical textbooks currently used in college courses are 0 and 8 years. Use the range rule of thumb to estimate the standard deviation.

Estimate the minimum and maximum ages for typical textbooks currently used in college courses, then use the range rule of thumb to estimate the standard deviation. Next, find the size of the sample required to estimate the mean age (in years) of textbooks currently used in college courses. Use a 90% confidence level and assume that the sample mean will be in error by no more than 0.25 year."

Solution for the problem

First we need ti find the estimation for the standard deviation using the Rule of thumb, with the following formula:

$s \approx \frac{R}{4}$

Where R is the range defined as :

$R = Max - Min = 8-0 = 8$

So then the deviation would be approximately:

$s \approx 4$

Important concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error (ME) 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".

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

And on this case we have that $ME =\pm 0.25$ and we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (2)

We can assume that the estimator for the population deviation from the rule of thumb is $\hat \sigma = s= 4$

The critical value for 90% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.05;0;1)", and we got $z_{\alpha/2}=1.64$ , replacing into formula (2) we got: