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1 year ago

A train can travel 744 miles in 3 hours. What is the unit rate that this train is traveling per hour?

Mathematics

1 answer:

Nataly [62]1 year ago

5 0

All you have to do is divide 744 by 3 to get the unit rate.

The unit rate is 248 miles per hours

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The article "Expectation Analysis of the Probability of Failure for Water Supply Pipes"† proposed using the Poisson distribution

oksian1 [2.3K]

Answer:

a. P(X ≤ 5) = 0.999

b. P(X > λ+λ) = P(X > 2) = 0.080

Step-by-step explanation:

We model this randome variable with a Poisson distribution, with parameter λ=1.

We have to calculate, using this distribution, P(X ≤ 5).

The probability of k pipeline failures can be calculated with the following equation:

$P(k)=\lambda^{k} \cdot e^{-\lambda}/k!=1^{k} \cdot e^{-1}/k!=e^{-1}/k!$

Then, we can calculate P(X ≤ 5) as:

$P(X\leq5)=P(0)+P(1)+P(2)+P(4)+P(5)\\\\\\P(0)=1^{0} \cdot e^{-1}/0!=1*0.3679/1=0.368\\\\P(1)=1^{1} \cdot e^{-1}/1!=1*0.3679/1=0.368\\\\P(2)=1^{2} \cdot e^{-1}/2!=1*0.3679/2=0.184\\\\P(3)=1^{3} \cdot e^{-1}/3!=1*0.3679/6=0.061\\\\P(4)=1^{4} \cdot e^{-1}/4!=1*0.3679/24=0.015\\\\P(5)=1^{5} \cdot e^{-1}/5!=1*0.3679/120=0.003\\\\\\P(X\leq5)=0.368+0.368+0.184+0.061+0.015+0.003=0.999$

The standard deviation of the Poisson deistribution is equal to its parameter λ=1, so the probability that X exceeds its mean value by more than one standard deviation (X>1+1=2) can be calculated as:

$P(X>2)=1-(P(0)+P(1)+P(2))\\\\\\P(0)=1^{0} \cdot e^{-1}/0!=1*0.3679/1=0.368\\\\P(1)=1^{1} \cdot e^{-1}/1!=1*0.3679/1=0.368\\\\P(2)=1^{2} \cdot e^{-1}/2!=1*0.3679/2=0.184\\\\\\P(X>2)=1-(0.368+0.368+0.184)=1-0.920=0.080$

4 0

2 years ago

A random sample of 35 undergraduate students who completed two years of college were asked to take a basic mathematics test. The

lisov135 [29]

Answer:

$(75.1 -72.1) -1.66 \sqrt{\frac{12.8^2}{35} +\frac{14.6^2}{50}}= -1.96$

$(75.1 -72.1) +1.66 \sqrt{\frac{12.8^2}{35} +\frac{14.6^2}{50}}= 7.96$

And the confidence interval would be given by:

$-1.96 \leq \mu_1 -\mu_2 \leq 7.96$

And since the confidence interval contains the value 0 we have enough evidence to conclude that we don't have significant differences between the two means at 10% of significance.

Step-by-step explanation:

For this case we have the following info given :

$\bar X_1= 75.1$ represent the sample mean for the scores of the undergraduate students

$s_1 = 12.8$ represent the standard deviation for the undergraduate students

$n_1 =35$ the sample size for the undergraduate

$\bar X_2= 72.1$ represent the sample mean for the scores of the high school students

$s_2 = 14.6$ represent the standard deviation for the high school students

$n_2 =50$ the sample size for the high school

The confidence interval for the true difference of means is given by:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2} \sqrt{\frac{s^2_1}{n_1} +\frac{s^2_2}{n_2}}$

The degrees of freedom are given by:

$df=n_1 +n_2 -2= 35+50-2=83$

The confidence level is 90% and the significance level is $\alpha=0.1$ and $\alpha/2 =0.05$ then the critical value would be:

$t_{\alpha/2}= 1.99$

And replacing the info we got:

$(75.1 -72.1) -1.66 \sqrt{\frac{12.8^2}{35} +\frac{14.6^2}{50}}= -1.96$

$(75.1 -72.1) +1.66 \sqrt{\frac{12.8^2}{35} +\frac{14.6^2}{50}}= 7.96$

And the confidence interval would be given by:

$-1.96 \leq \mu_1 -\mu_2 \leq 7.96$

And since the confidence interval contains the value 0 we have enough evidence to conclude that we don't have significant differences between the two means at 10% of significance.

8 0

1 year ago

If the foreign exchange rate between the japanese yen and the euro is 190:1, how many yen will equal 10 euros?

alexgriva [62]

Alright, lets get started.

The foreign exchange rate between the japanese yen and the euro is 190:1 given.

It means 1 euro = 190 yen

We are asked to find how many yen will be equal to 10 euros.

Means we need to multiply given euros with 190 because 1 euro = 190 yen

Hence 10 euros $= 190 * 10$ yen

10 euros = 1900 yen : Answer

Hope it will help :)

4 0

2 years ago

Felipe trabaja en una construcción ayuda a cotizar materiales entre ellos cables para diversos propósitos el arquitecto le pidió

Alekssandra [29.7K]

Answer:

a) 0.64mm

b) 7/25

Step-by-step explanation:

Felipe trabaja en una construcción ayuda a cotizar materiales entre ellos cables para diversos propósitos.El arquitecto le pidió cotizar un cable de 16/25 mm de diámetro. en los catálogos disponibles en as tiendas las medidas aparecen expresadas en números decimales como se muestra en la imagen

¿Que debe hacer felipe para saber el diámetro del cable que pidió el arquitecto?

¿que medida en forma de fracción le corresponde al cable que mide 0.28? ¿como lo determinaste? es urgenteeee GRACIAS

a) Dada la dimensión fraccionaria del cable expresada como 16/25 mm, dado que Felipe debe expresar esta fracción en decimal para obtener la medida requerida, dividiremos la expresión usando una división larga como se muestra en el anexo. Desde el archivo adjunto;

16/25 mm = 0,64 mm

b) La medida fraccionaria corresponde al cable que mide 0.28 se expresa como se muestra. Convertir 0,28 a fracción.

0.28 = 28/100 (Tenga en cuenta que dividimos por 100 porque hay dos valores decimales después del punto decimal)

Sobre la simplificación en su término más bajo

28/100 = 4 * 7/4 * 25

28/100 = 4/4 * 7/25

28/100 = 1 * 7/25

28/100 = 7/25

Por lo tanto, la medida fraccionaria que corresponde al cable que mide 0.28 es 7/25.

8 0

2 years ago

If PQ and RS intersect to form four right angles which statement is true

Rus_ich [418]

Given that PQ and RS intersect to form four right angles, then they form an angle of 90 degrees, this implies that:
if the meet at point O,
then;
∠POR=∠POS=∠QOS=∠ROQ=90°
Therefore the correct statement is:
PQ is perpendicular to RS
that is to mean:
PQ⊥RS
The answer is C.

7 0

1 year ago

Read 2 more answers