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iris [78.8K]
3 years ago
11

A company interested in lumbering rights for a certain tract of slash pine trees is told that the mean diameter of these trees i

s 19 inches with a standard deviation of 2.3 inches. Assume the distribution of diameters is roughly mound-shaped. (a) What fraction of the trees will have diameters between 14.4 and 25.9 inches? 0.75 Incorrect: Your answer is incorrect. (b) What fraction of the trees will have diameters greater than 21.3 inches?
Mathematics
1 answer:
Fofino [41]3 years ago
3 0

Answer:

97.5 %

15.7 %

Step-by-step explanation:

\mu = Mean = 19

\sigma = Standard deviation = 2.3

a)

\mu+x\sigma=25.9\\\Rightarrow 19+x\times 2.3=25.9\\\Rightarrow x=\frac{25.9-19}{2.3}\\\Rightarrow x=3

\mu-x\sigma=14.4\\\Rightarrow 19-x\times 2.3=14.4\\\Rightarrow x=\frac{19-14.4}{-2.3}\\\Rightarrow x=2

From the empirical rule we get that the percentage of trees between 14.4 and 25.9 inches is 13.6+34.1+34.1+13.6+2.1 = 97.5 %

b)

\mu+x\sigma=21.3\\\Rightarrow 19+x\times 2.3=21.3\\\Rightarrow x=\frac{21.3-19}{2.3}\\\Rightarrow x=1

The fraction of tree under 21.3 inches is 34.1.

Hence the fraction of trees above the diameter of 21.3 inches is 13.6+2.1 = 15.7 %

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Mona's math certificate is 10 inches tall and 14 inches wide. Mona wants to put the certificate in a fancy frame that costs $1.0
swat32

Answer:

$48.96

Step-by-step explanation:

Given data

Length= 10inches

Width=14 inches

Let us find the perimeter of the  certificate

P=2L+2W

P= 2*10+2*14

P=20+28

P= 48 inches

Hence if 1 inche cost $1.02

Then 48 inches will cost x

cross multiply we

x= 48*1.02

x= $48.96

Hence it will cost $48.96 to frame the certificate

6 0
3 years ago
Point J is on line segment IK. Given JK = 2x – 1, IK = 3x + 2,
Serhud [2]

Answer:

JK=7

Step-by-step explanation:

From the line segment, since J is on it ,it means the line segment is

represented as I J K

from this illustration, we can say that the longest part of the line segment is from I to K

this means that, IJ +JK =IK

making JK the subject,

JK= IK - IJ

but from the question, JK=2x-1 , IK=3x+2 and IJ=3x-5

substituting them in the expression,

2x-1 =3x+2 -(3x-5)

solving for x

2x-1 =3x+2-3x+5

2x-1 =0+7

2x-1 =7

2x=1+7

2x=8

dividing through by 2

2x/2 =8/2

x=4

but the question says we should find the numerical value for JK

but from the line segment,

JK=2x-1

but now we know the value of x to be 2

so substituting it in the formula

JK= 2(4)-1

JK=8-1

JK=7

therefore, the numerical value for JK is 7

4 0
3 years ago
Segment addition with variables
oksian1 [2.3K]

<em>x equals 22</em>

<h2>Explanation:</h2>

____________________________________________

The Segment Postulate states the following:

<em>Given two end points A and B, a third point C lines on the segment AB if and only if the distances between the points satisfy the equation:</em>

\overline{AB}=\overline{AC}+\overline{CB}

____________________________________________

From the figure:

\overline{AC}=8+x \\ \\ \overline{CB}=10 \\ \\ \overline{AB}=40

Our goal is to find x:

\overline{AB}=\overline{AC}+\overline{CB} \\ \\ Substituting \ values: \\ \\ 40=(8+x)+10 \\ \\ 18+x=40 \\ \\ Subtracting \ 18 \ from \ both \ sides: \\ \\ 18-18+x=40-18 \\ \\ \boxed{x=22}

<h2>Learn more:</h2>

Dilation: brainly.com/question/2501119

#LearnWithBrainly

4 0
2 years ago
Your neighbor has a bag with 5 oranges and 7 apples in it. You will be receiving two pieces of fruit from your neighbor. What is
Snezhnost [94]

Answer:

31.82% probability that you will receive 2 apples.

Step-by-step explanation:

The fruits are removed from the bag, which means that the hypergeometric distribution is used to solve this question.

Hypergeometric distribution:

The probability of x sucesses is given by the following formula:

P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}

In which:

x is the number of sucesses.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

C_{n,x} is the number of different combinations of x objects from a set of n elements, given by the following formula.

C_{n,x} = \frac{n!}{x!(n-x)!}

In this question:

5 + 7 = 12 total fruits, which means that N = 12

7 apples, which means that k = 7

You receive 2 fruits, which means that n = 2

What is the probability, in percent, that you will receive 2 apples, assuming she removes them from the bag in random order?

This is, as a proportion, P(X = 2). So

P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}

P(X = 2) = h(2,12,2,7) = \frac{C_{7,2}*C_{5,0}}{C_{12,2}} = 0.3182

0.3182*100% = 31.82%

31.82% probability that you will receive 2 apples.

4 0
3 years ago
The sum of person x and person y is 2640. if person x's income is 20% more than person y, find person x's income.
Masja [62]

Answer:

I do not understand she question do you mean the sum of their income is 2640

if so, then the answer is 440 to be x income

Step-by-step explanation:

x income = 20% or 1/5 of y income

y income = 5 of x income

we know that the sum of their income = 2640

which means that

x + y = 2640 =

1/5y + y = 2640

6y/5 = 2640

cross multiply to give us

6y = 5(2640)

6y = 13200

divide through by 6 to give us,

6y/6 = 13200/6

y = 2200

since we know that x income is 20% y income,

therefore, x income =

20/100 * 2200

= 440

therefore,

x income = 440

y income = 2200

5 0
2 years ago
Read 2 more answers
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