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2 years ago

7

The age of trees in a forest is known to be approximately normal with an average age of 40 years and a standard deviation of 10

years. What is the standardized score for a tree that is 34 years old?

1 answer:

Keith_Richards [23]2 years ago

6 0

Answer: D. -0.6

Step-by-step explanation:

Z score formula= x-mean/ SD

34-40/10= -3/5= -0.6

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The circumference of the inner circle is 44 ft. The distance between the inner circle and the outer circle is 3 ft. By how many

Citrus2011 [14]

Answer: 18.86 feet

Step-by-step explanation:

The formula for determining the circumference of a circle is expressed as

Circumference = πD

Where D represents the diameter of the circle.

The circumference of the inner circle is 44 ft. It means that

22/7 × D = 44

22D = 7 × 44 = 308

D = 308/22

D = 14 ft

The distance between the inner circle and the outer circle is 3 ft. This means that the diameter of the outer circle would be

14 + 3 + 3 = 20 ft

Circumference of the outer circle is

22/7 × 20 = 62.86 ft

The number of feet by which the circumference of outer circle is greater than the circumference of the inner circle is

62.86 - 44 = 18.86 feet

5 0

3 years ago

78 is what percent of 110

irinina [24]

Answer: 70.909090909091%

Step-by-step explanation: Reading through the problem we have <em>78 is</em>, that's 78 equals, <em>what percent</em>, x/100, <em>of 110</em>, times 110.

It's important to understand that <em>percent</em> means over 100 so what percent would simply mean <em>x/100</em> or any variable but I will be using x.

So we have the equation $78 = \frac{x}{100} *110$

So cross canceling the 110 and 100 to 11 and 10, we have $78 = \frac{11x}{10}$

Multiply both sides by 10 to get rid

of the fraction and we have 780 = 11x.

Now divide both sides by 11 and 70.909090909091 = x.

So, 78 is 70.909090909091% of 110.

Work is attached in the image provided.

8 0

3 years ago

A pigpen is to be enclosed using 640 m of fencing along three of its sides, the fourth side being a barn. Determine the dimensio

Basile [38]

Answer:

$W_{max}=480m\\ L_{max}=160m$

Step-by-step explanation:

Since we know we only have 640 feet of fence available, we know that L + W + L = 640, $\implies$ 2L + W = 640. This allows us to represent the width, W, in terms of L: W = 640 – 2L

Remember, the area of a rectangle is equal to the product of its width and length, therefore,

$A_{\rm pigpen}=L(640-2L)\implies 640L-2L^2$

Notice that, quadratic has been vertically reflected, since the coefficient on the squared term is negative, so the graph will open downwards, and the vertex will be a maximum value for the area.

recall,

$x_{max}=-b/2a$
$f(x)_{max}=f(x_{max})$

Since our function is A(L)=640L-2L², we get

a=-2
b=640

plug in the value of a and b into the first formula:

$L_{max}=-(640)/2(-2)\implies 160$

$A(L)_{max}=640(160)-2(160)^2\implies 76800$

hence,the dimensions of the pen that will maximize the area are<u> </u><u>L=</u><u>1</u><u>6</u><u>0</u><u>m</u><u> </u>and<u> </u><u>W=</u><u>7</u><u>6</u><u>8</u><u>0</u><u>0</u><u>/</u><u>1</u><u>6</u><u>0</u><u>=</u><u>4</u><u>8</u><u>0</u><u>m</u>

and we're done!

3 0

2 years ago

How can i use decimal models to add decimals?

Vinil7 [7]

<span>Understand that a decimal is any number written in the base-10 system....

Represent decimals using area models.

State the fraction (tenths or hundredths) that is equivalent to a given decimal.
<span>
Compare the values of decimals (tenths or hundredths) using area models and/or a number line.</span></span>

3 0

2 years ago

Read 2 more answers

Can someone explain me this one

JulsSmile [24]

Well the math you would do is 3346/7. That equals 478. As a fraction in simplest form you could write 478/1

7 0

3 years ago

Read 2 more answers