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3 years ago

5

A family wants to save for college tuition for their daughter. What continuous yearly interest rate r% is needed in their saving

s account if their deposits of $4700 per year are to grow to $110,000 in 14 years? Assume that they make deposits continuously throughout the year.

1 answer:

sergey [27]3 years ago

4 0

Answer:

The continuous yearly interest is 22.5% per year.

Step-by-step explanation:

Continuous yearly interest:

Continuous yearly interest is defined as the sum of the interest comes from principle and the interest comes from interest.

The formula for continuous interest yearly is

$A=Pe^{rt}$

where A = The final amount =$110,000

P= principle =$4,700

r= rate of interest

t= time (in year)= 14 years

$\therefore 110,000= 4,700e^{r\times 14}$

$\Rightarrow e^{14r}= \frac{110,000}{4,700}$

Taking ln both sides

$\Rightarrow ln e^{14r}= ln(\frac{110,000}{4,700})$

$\Rightarrow {14r}= ln(\frac{1100}{47})$

$\Rightarrow r=\frac{ln( \frac{1100}{47})}{14}$

$\Rightarrow r = 0.225$ (approx)

The continuous yearly interest is 0.225 = 22.5% per year.

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g A certain financial services company uses surveys of adults age 18 and older to determine if personal financial fitness is cha

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Answer:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

$z=\frac{0.410-0.35}{\sqrt{0.385(1-0.385)(\frac{1}{1000}+\frac{1}{700})}}=2.502$

$p_v =2*P(Z>2.502)= 0.0123$

Comparing the p value with the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to to reject the null hypothesis, and we can say that the proportion analyzed is significantly different between the two groups at 5% of significance.

Step-by-step explanation:

Data given and notation

$X_{1}=410$ represent the number of people indicating that their financial security was more than fair for the recent year

$X_{2}=245$ represent the number of people indicating that their financial security was more than fair for the year before

$n_{1}=1000$ sample 1 selected

$n_{2}=700$ sample 2 selected

$p_{1}=\frac{410}{1000}=0.410$ represent the proportion estimated of indicating that their financial security was more than fair this year

$p_{2}=\frac{245}{700}=0.35$ represent the proportion estimated of indicating that their financial security was more than fair the year before

$\hat p$ represent the pooled estimate of p

z would represent the statistic (variable of interest)

$p_v$ represent the value for the test (variable of interest)

$\alpha$ significance level given

Concepts and formulas to use

We need to conduct a hypothesis in order to check if is there is a difference between the two proportions, the system of hypothesis would be:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

We need to apply a z test to compare proportions, and the statistic is given by:

$z=\frac{p_{1}-p_{2}}{\sqrt{\hat p (1-\hat p)(\frac{1}{n_{1}}+\frac{1}{n_{2}})}}$ (1)

Where $\hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{410+245}{1000+700}=0.385$

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

Calculate the statistic

Replacing in formula (1) the values obtained we got this:

$z=\frac{0.410-0.35}{\sqrt{0.385(1-0.385)(\frac{1}{1000}+\frac{1}{700})}}=2.502$

Statistical decision

Since is a two sided test the p value would be:

$p_v =2*P(Z>2.502)= 0.0123$

Comparing the p value with the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to to reject the null hypothesis, and we can say that the proportion analyzed is significantly different between the two groups at 5% of significance.

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3 years ago

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serious [3.7K]

Answer:

5 hours

Step-by-step explanation:

given :

Distance between the cities = 540 miles

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TO CALCULATE THE TIME TAKEN BY MOTORCYCLE TO COVER THE TOTAL DISTANCE WE USE THE FORMULA :

$\frac{DISTANCE}{SPEED}$

By putting given values in the formula we get :

$\frac{540}{48}$

= 11.25 hours

Now, We are given that for a car to cover the same distance it takes 2.25 hours less than the time taken by motorcycle

⇒ 11.25 hours - 2.25 hours

⇒ 9 hours

Thus , Time taken by car to cover the same distance is 9 hours .

Now to calculate speed of car by using formula:

$\frac{distance}{time}$

$\frac{540}{9}$

= 60 mph

Let t be the time taken to meet if they start moving towards each other.

So distance covered by motorcycle in t hours is

speed\times time

= 48t miles

Distance covered by car in t hours is

speed\times time

= 60t miles

⇒ 60t + 48t =540

⇒ 108t = 540

⇒ t= 5 hours

Therefore, time taken to meet if they start moving towards each other is 5 hours.

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3 years ago