Use the graph to find the slope of the line. Tell with the slope means in this context

1. A taxicab ride costs $1.30 plus $0.85 per mile. If the total cost of the trip

Tems11 [23]

The passenger travelled 12 miles

5 0

3 years ago

You have 800 feet of fencing and you want to make two fenced in enclosures by splitting one enclosure in half. What are the larg

katovenus [111]

Problema Solution

You have 800 feet of fencing and you want to make two fenced in enclosures by splitting one enclosure in half. What are the largest dimensions of this enclosure that you could build?

Answer provided by our tutors

Make a drawing and denote:

x = half of the length of the enclosure

2x = the length of the enclosure

y = the width of the enclosure

P = 800 ft the perimeter

The perimeter of the two enclosures can be expressed P = 4x + 2y thus

4x + 3y = 800

Solving for y:

........

click here to see all the equation solution steps

........

y = 800/3 - 4x/3

The area of the two enclosure is A = 2xy.

Substituting y = 800/3 - 4x/3 in A = 2xy we get

A = 2x(800/3 - 4x/3)

A =1600x/3 - 8x^2/3

We need to find the x for which the parabolic function A = (- 8/3)x^2 + (1600/3)x has maximum:

x max = -b/2a, a = (-8/3), b = 1600/3

x max = (-1600/3)/(2*(-8/3))

x max = 100 ft

y = 800/3 - 4*100/3

y = 133.33 ft

2x = 2*100

2x = 200 ft

3 0

3 years ago

Solve the system of equations<br> 3x+4y+12<br> 9x-2y=15

Mrrafil [7]

3x+4y=12
9x-2y=15
we will use elimination
multiply 3x+4y=12 by -3

-9x-12y=-36
9x-2y=15
_________ add
-14y=-21
÷-14 both sides
y=1.5
find x
3x+4 (1.5)=12
3x+6=12
-6 both sides
3x=6
÷3 both sides
x=2

x=2
y=1.5

3 0

3 years ago

Andrew plans to retire in 32 years. He plans to invest part of his retirement funds in stocks, so he seeks out information on pa

Debora [2.8K]

Answer:

a) 0.0885 = 8.85% probability that the mean annual return on common stocks over the next 40 years will exceed 13%.

b) 0.4129 = 41.29% probability that the mean return will be less than 8%

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Mean 8.7% and standard deviation 20.2%.

This means that $\mu = 8.7, \sigma = 20.2$

40 years:

This means that $n = 40, s = \frac{20.2}{\sqrt{40}}$

(a) What is the probability (assuming that the past pattern of variation continues) that the mean annual return on common stocks over the next 40 years will exceed 13%?

This is 1 subtracted by the pvalue of Z when X = 13. So

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$