PLEASE HELP BRAINLIEST!!!

Twenty planes are at an airport. Eight planes take off, then five planes land, then 7

steposvetlana [31]

Answer:

19

Step-by-step explanation:

20 - 8 = 12

12 + 5 = 17

17 - 7 = 10

10 + 9 = 19

4 0

3 years ago

100 POINTS Coronavirus cases rose from 23 cases on October 3rd to 103 cases on November 3rd .What was the percent increase based

evablogger [386]

Answer:

<h2><em>348% increase</em></h2>

Step-by-step explanation:

103 - 23 / 23 = 3.47826

3.48 x 100% = 348%

8 0

3 years ago

A random sample of 16 statistics examinations was taken. The average sample score was 76.2 with a sample variance of 144. The 99

dlinn [17]

99% confidence interval for the population average examination score is between a lower limit of 67.35 and an upper limit of 85.05. The correct option is C.

<h3>What is the margin of error in statistics?</h3>

The margin of error is a statistic that describes how much random sampling error there is in survey results. One should have less faith that a poll's findings would accurately reflect those of a population census the higher the margin of error.

The interval will be calculated as below:-

Confidence interval = mean +/- margin of error (E)

mean = 76.2

variance = 144

sd = sqrt(variance) = sqrt(144) = 12

n = 16

Degree of freedom (df) = n - 1 = 16- 1 = 15

Confidence level (C) = 99% = 0.99

Significance level = 1 - C = 1 - 0.99 = 0.01 = 1%

t-value corresponding to 15 df and 1% significance level is 2.95

The margin of error will be:-

E = t×sd/√n = 2.95 × 12/√16 = 8.85

The interval will be:-

Lower limit = mean - E = 76.2 - 8.85 = 67.35

Upper limit = mean + E = 76.2 + 8.85 = 85.05

Therefore, the 99% confidence interval for the population average examination score is between a lower limit of 67.35 and an upper limit of 85.05. The correct option is C.

To know more about margin of error follow

brainly.com/question/24289590

#SPJ1

4 0

2 years ago

IS 10×1000 a multiplication fact?

Tanya [424]

Yes if u can multiply 10 by 1000 then it is a multiplication fact

4 0

3 years ago

Read 2 more answers

Could somebody help me with Geometry? THANKS!!!!!!!!!!!!!!!!!!!!!

Vedmedyk [2.9K]

I'll do problem 1 to get you started.

The answer to problem 1 is <u>3400 miles</u>

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Explanation for problem 1:

We're asked to find the perimeter, which is the total distance around the exterior or outside. In other words, we need to add up the four side lengths of this quadrilateral.

We'll need the distance formula to find the lengths of the slanted sides AB and BC

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Let's first find the length of segment AB

A = (x1,y1) = (0,0)

B = (x2,y2) = (400,300)

d = Length of AB

$d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}\\\\d = \sqrt{(0-400)^2 + (0-300)^2}\\\\d = \sqrt{(-400)^2 + (-300)^2}\\\\d = \sqrt{160000 + 90000}\\\\d = \sqrt{250000}\\\\d = 500\\\\$

The distance from A to B is 500 miles. This is the same as saying segment AB is 500 miles long.

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Now find the length of segment BC

B = (x1,y1) = (400,300)

C = (x2,y2) = (-800,800)

d = length of BC

$d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}\\\\d = \sqrt{(400-(-800))^2 + (300-800)^2}\\\\d = \sqrt{(400+800)^2 + (300-800)^2}\\\\d = \sqrt{(1200)^2 + (-500)^2}\\\\d = \sqrt{1440000 + 250000}\\\\d = \sqrt{1690000}\\\\d = 1300\\\\$

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The length of CD is fairly easy to find without needing the distance formula. This is because it is a vertical line. We subtract the y coordinates of C and D to get 800-0 = 800. So CD is 800 miles long.

Segment DA is a similar story. But we subtract the x coordinates. This only works for horizontal lines. DA is 800 miles long because |-800-0| = 800. Absolute value is used to make sure the distance is never negative.

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To summarize everything so far, we found these four side lengths

AB = 500
BC = 1300
CD = 800
DA = 800

The perimeter is going to be the sum of those four sides, leading to...

perimeter = sum of sides

perimeter = AB+BC+CD+DA

perimeter = 500+1300+800+800

perimeter = 3400 miles

This is the total distance traveled if you started at city A, went to B, then to C, then to D, and then finally went back to A.

5 0

3 years ago

Read 2 more answers