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2 years ago

Write an expression using multiplication and addition with a sum of 16. (PLZ HELP!!!!)

Mathematics

1 answer:

Svetach [21]2 years ago

7 0

Write an expression using multiplication and addition with a sum of 16:

2 x 6 +4

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Pls help me I really need help on this

Svetlanka [38]

Answer:

Step-by-step explanation:

i just took the test

7 0

2 years ago

If 40% of a number is 56 what was the original number

lisov135 [29]

$\begin{array}{ccc}100\%&-&x\\40\%&-56\end{array}\ \ \ |cross\ multiply\\\\40x=56\times100\\40x=5600\ \ \ \ \ |divide\ both\ sides\ by\ 40\\\\\boxed{x=140}$

7 0

3 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:

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

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

6 0

2 years ago

1. The ratio of the measures of the sides of a triangle is 5:6:8, and

julsineya [31]

Answer:

42mm

Step-by-step explanation:

Let the shortest side of the triangle be 5x, the middle side be 6x, and the longest side be 8x.

5x+6x+8x = 159.6

19x = 159.6

x = 159.6 ÷ 19

x = 8.4

Shortest side of triangle (5x) = 8.4 × 5

= 42

4 0

2 years ago

Find the coordinates of the midpoint between point A(18, -6) and the origin.

Sedbober [7]

Mid point b/w (18,-6),(0,0)
X = 0+18/2 = 9
y = 0-6/2 = -3
thus mid point is (9,-3)

4 0

3 years ago