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3 years ago

Help me please !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mathematics

1 answer:

RideAnS [48]3 years ago

6 0

We have an geometric progression:
nth term=a₁r^(n-1)
nth term=y
a₁ is the first term=10
r=common ratio=a₂/a₁=20/10=2
n=x
nth term=a₁r^(n-1)

Therefore
y=10.2^(x-1)=(2*5)2^(x-1)=(5)2^(x-1+1)=(5)2^x

Answer: y=[5][(2)]^[x]

To check:
if x=1 ⇒y=(5)(2)=10
if x=2 ⇒y=(5)(4)=20
if x=3 ⇒y=(5)(8)=40

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The average high-school teacher annual salary is $43,000. Let teacher salary be normally distributed with a standard deviation o

Dvinal [7]

Answer:

a) 0.219

b) 0.02

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 43000, \sigma = 18000$

a. What percent of high school teachers make between $40,000 and $50,000?

This is the pvalue of Z when X = 50,000 subtracted by the pvalue of Z when X = 40,000.

X = 50,000

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

$Z = \frac{50000 - 43000}{18000}$

$Z = 0.39$

$Z = 0.39$ has a pvalue of 0.6517.

X = 40,000

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

$Z = \frac{40000 - 43000}{18000}$

$Z = -0.17$

$Z = -0.17$ has a pvalue of 0.4325

So 0.6517 - 0.4325 = 0.219 = 21.9% of high school teachers make between $40,000 and $50,000.

b. What percent of high school teachers make more than $80,000?

This is 1 subtracted by the pvalue of Z when X = 80000. SO

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

$Z = \frac{80000 - 43000}{18000}$

$Z = 2.06$

$Z = 2.06$ has a pvalue of 0.9803.

So 1-0.9803 = 0.0197 = 0.02 = 2% of high school teachers make more than $80,000.

6 0

3 years ago

Find the area to this

Vinvika [58]

Answer:

Step-by-step explanation:

6 0

3 years ago

Solve the equation 4n-18=52

muminat

Answer:
n = 35/2
Hope this helps! :)

4 0

3 years ago

Read 2 more answers

a packe of cards conatins 4 red and 5 black cards. a hand of 5 cards is drawn without replacment. What is the proablity of all f

Vladimir79 [104]

Answer: Our required probability is 0.3387.

Step-by-step explanation:

Since we have given that

Number of red cards = 4

Number of black cards = 5

Number of cards drawn = 5

We need to find the probability of getting exactly three black cards.

Probability of getting a black card = $\dfrac{5}{9}$

Probability of getting a red card = $\dfrac{4}{9}$

So, using "Binomial distribution", let X be the number of black cards:

$P(X=3)=^5C_3(\dfrac{5}{9})^3(\dfrac{4}{9})^2\\\\P(X=3)=0.3387$

Hence, our required probability is 0.3387.

5 0

3 years ago

Samuel took an antique clock that his grandfather had purchased, to be appraised. The appraiser evaluated the current price of t

andrew11 [14]

This is an exponential growth problem. Exponential growth can be expressed mathematically in the following way:
$y=a (1+r)^{t}$ .
Parameter a presents initial amount.
Parameter r is percentage increase.
Parameter t is time.
An equation that would describe given problem is:
$y=400 (1+0.02)^{t}$
t is the time in years.
I attached the graph of this function.

6 0

4 years ago