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3 years ago

Please help me answer.

Mathematics

2 answers:

ololo11 [35]3 years ago

7 0

Answer:

D. 251.2 feet

Step-by-step explanation:

On carefully observing the diagram,it can be seen that 80 feet is the diameter of the circular ride, i.e.,the circle,in this case.

The radius of the circle will be half the diameter,r=(80/2) feet=40 feet

The distance of one complete loop of this circular path will be the circumference of the circle.

So, Circumference

=2*π*r

=2*3.14*40 feet

=251.2 feet [ANS]

gtnhenbr [62]3 years ago

7 0

Answer:

Step-by-step explanation:

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Four pieces of rope of unknown (but equal) length and 10 more feet of rope are attached together. The resulting rope is 30 feet

zlopas [31]

Answer:

5 feet each

Step-by-step explanation:

So we know that 4 pieces of rope out of 5 are equal. So, we simply subtract 10 from 30 for that 10-foot piece of rope, which leaves us with 20. Divide 20 by 4 (since there is 4 pieces of rope of equal value) and it leaves us with 5 feet.

Hope I helped! :)

7 0

2 years ago

The ages of a random sample of five university professors are 39, 54, 61, 72, and 59. Using this information, find a 99% confide

blsea [12.9K]

Answer:

$38.898 \leq \sigma^2 \leq 2792.356$

Now we just take square root on both sides of the interval and we got:

$6.237 \leq \sigma \leq 52.843$

Step-by-step explanation:

Data given and notation

34,59,61,71,59

We can calculate the sample standard deviation with the following formula:

$s^2= \frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$s= \sqrt{s^2}$

s=12.021 represent the sample standard deviation

$\bar x$ represent the sample mean

n=5 the sample size

Confidence=99% or 0.99

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 mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=5-1=4$

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical values.

The excel commands would be: "=CHISQ.INV(0.005,4)" "=CHISQ.INV(1-0.005,4)". so for this case the critical values are:

$\chi^2_{\alpha/2}=14.860$

$\chi^2_{1- \alpha/2}=0.207$

And replacing into the formula for the interval we got:

$\frac{(4)(12.021)^2}{14.860} \leq \sigma^2 \leq \frac{(4)(12.021)^2}{0.207}$

$38.898 \leq \sigma^2 \leq 2792.356$

Now we just take square root on both sides of the interval and we got:

$6.237 \leq \sigma \leq 52.843$

3 0

3 years ago

Read 2 more answers

A surf shop rents surfboards and charges x dollars for one rental day. it gives a discount for a weekly seven day rental and onl

Artyom0805 [142]

A. The shop charges $8.517 for a one-day rental

B. The shop charges $42.857 for a weekly rental.

Step-by-step explanation:

Step 1; The shop charges $x for a one-day rental and $5x for a weekly rental. Assume $x = a and $5x = b, from this we can write,

5a = b, take this as equation 1.

Step 2; The shop had a total sale of $600 by renting 20 boards for a one-day rental and 10 boards for a weekly rental. So,

20a + 10b = 600, take this as equation 2.

Substituting equation 1 in 2, we get

20a + 10 (5a) = 600,

20a + 50a = 600, a = 600 / 70,

a = $8.5714.

From equation 1, 5a = b,

5 × $8.5714 = b,

b = $42.857.

So for a one-day rental, the shop charges $8.5714 and for a weekly rental it charges $42.857.

6 0

3 years ago

How do I count by twelfths

Korvikt [17]

12, x 1 = 12

12 x 2 =24

12 x 3 = 36

12 x 4 =48

12 x 5= 60

12 x 6 =72

12 x 7 = 84

12 x 8= 96

12 x 9= 108

12 x 10 = 120

12 x 11=132

12x 12= 144

hope this helps

8 0

3 years ago

What is the average rate of change of the function g(x) = 4x from x = 1 to x = 5?

Fittoniya [83]

Answer:

$\displaystyle 4$

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Algebra I

Function Notation
Interval Notation - [a, b]
Average Rate of Change: $\displaystyle \displaystyle \frac{f(b) - f(a)}{b - a}$

Step-by-step explanation:

Step 1: Define

g(x) = 4x

Interval [1, 5]

Step 2: Find Change

Substitute in function and points [Average Rate of Change]: $\displaystyle \displaystyle \frac{4(5) - 4(1)}{5 - 1}$
[Fraction] Multiply: $\displaystyle \displaystyle \frac{20 - 4}{5 - 1}$
[Fraction] Subtract: $\displaystyle \displaystyle \frac{16}{4}$
[Fraction] Divide: $\displaystyle 4$

7 0

3 years ago