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Your task is to build a road joining a ranch to a highway that enables drivers to reach the city in the shortest time. The perpe

lubasha [3.4K]

Answer:

(a)In the attachment

(b)The road of length 35.79 km should be built such that it joins the highway at 19.52km from the perpendicular point P.

Step-by-step explanation:

(a)In the attachment

(b)The distance that enables the driver to reach the city in the shortest time is denoted by the Straight Line RM (from the Ranch to Point M)

First, let us determine length of line RM.

Using Pythagoras theorem

$|RM|^{2}=30^2+x^2\\|RM|=\sqrt{30^2+x^2}$

The Speed limit on the Road is 60 km/h and 110 km/h on the highway.

Time Taken = Distance/Time

Time taken on the road $=\frac{\sqrt{30^2+x^2}}{60}$

Time taken on the highway $=\frac{50-x}{110}$

Total time taken to travel, T $=\frac{\sqrt{30^2+x^2}}{60}+\frac{50-x}{110}$

Minimum time taken occurs when the derivative of T equals 0.

$T^{'}=\frac{x}{60\sqrt{30^2+x^2}}-\frac{1}{110}\\\frac{x}{60\sqrt{30^2+x^2}}-\frac{1}{110}=0\\\frac{x}{60\sqrt{30^2+x^2}}=\frac{1}{110}\\110x=60\sqrt{30^2+x^2}\\$

Square both sides

$12100x^2=3600(30^2+x^2)\\12100x^2=3240000+3600x^2\\12100x^2-3600x^2=3240000\\8500x^2=3240000\\x^2=\frac{3240000}{8500} =381.18\\x=\sqrt{381.18} =19.52$

The road should be built such that it joins the highway at 19.52km from the point P.

In fact,

$|RM|=\sqrt{30^2+19.52^2}=35.79km$

4 0

3 years ago

Sia has n apples. Nate has 6 more than her. How much does Nate have?

Alecsey [184]

Answer:

nate has n+6 apples

Step-by-step explanation:

5 0

2 years ago

Read 2 more answers

The radius of a sphere is 13 cm. What is the surface area of the sphere? Round to the nearest tenth

AlekseyPX

Answer:

2123.72 cm²

Step-by-step explanation:

Hope it helps

3 0

3 years ago

A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 420 gram setting. It is

anastassius [24]

Answer:

$t=\frac{424-420}{\frac{26}{\sqrt{61}}}=1.202$

$p_v =2*P(t_{(60)}>1.202)=0.234$

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can conclude that the true mean is NOT different from 420. So the specification is satisfied.

Step-by-step explanation:

Data given and notation

$\bar X=424$ represent the sample mean

$s=26$ represent the sample standard deviation

$n=61$ sample size

$\mu_o =420$ represent the value that we want to test

$\alpha=0.01$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

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

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is different from 420 or not, the system of hypothesis would be:

Null hypothesis: $\mu = 420$

Alternative hypothesis: $\mu \neq 420$

If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{424-420}{\frac{26}{\sqrt{61}}}=1.202$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=61-1=60$

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

$p_v =2*P(t_{(60)}>1.202)=0.234$

Conclusion

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can conclude that the true mean is NOT different from 420. So the specification is satisfied.

4 0

3 years ago

Present Value Hoew much shuold be deposited in an account paying 7.2% interest compounded monthly in order to have a balance of

jonny [76]

Answer:$6451.6 should be deposited.

Step-by-step explanation:

The principal was compounded monthly. This means that it was compounded 12 times in a year. So

n = 12

The rate at which the principal was compounded is 7.2%. So

r = 7.2/100 = 0.072

It was compounded for 3 years. So

t = 3

The formula for compound interest is

A = P(1+r/n)^nt

A = total amount in the account at the end of t years. A is given as $8000 Therefore,

8000 = P (1+0.072/12)^12×3

8000 = P(1+0.006)^36

8000 = P(1.006)^36

P = 8000/1.24

P = $6451.6

6 0

3 years ago