Simplify the expression. 28 + 18 ÷ 6 • (–3) <br><br> 19 27 –23

Two trains 500 miles apart accidentally are on the same track heading toward each other. The passenger train is traveling 80 mph

Natalka [10]

Answer:

2 miles

Step-by-step explanation:

Their combined speed (speed of closure) is 80 mph + 40 mph = 120 mph.

120 mi/h = 120 mi/(60 min) = 2 mi/min

The distance between the trains at the 1-minute mark is ...

(1 min) · (2 mi/min) = 2 mi

They were warned when two miles apart.

3 0

3 years ago

A study of the number of business lunches that executives in the insurance and banking industries claim as deductible expenses p

gizmo_the_mogwai [7]

Answer:

$t=\frac{9.1-8}{\sqrt{\frac{(1.9)^2}{40}+\frac{(2.1)^2}{50}}}}=2.604$

$p_v =2*P(t_{(88)}>2.604)=0.0108$

So the p value is a very low value and using any significance level for given $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and there is enough evidence to conclude that the two means are significantly different at 5%

Step-by-step explanation:

Data given and notation

$\bar X_{1}=9.1$ represent the mean for the sample 1

$\bar X_{2}=8$ represent the mean for the sample 2

$s_{1}=1.9$ represent the sample standard deviation for the sample 1

$s_{2}=2.1$ represent the sample standard deviation for the sample 2

$n_{1}=40$ sample size for the group 1

$n_{2}=50$ sample size for the group 2

t would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the mean are different , the system of hypothesis would be:

Null hypothesis: $\mu_{1} = \mu_{2}$

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

If we analyze the size for the samples both are higher than 30 and the population deviations are not given, so for this case is better apply a t test to compare means, and the statistic is given by:

$t=\frac{\bar X_{1}-\bar X_{2}}{\sqrt{\frac{s^2_{1}}{n_{1}}+\frac{s^2_{2}}{n_{2}}}}$ (1)

t-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

We can replace in formula (1) the results obtained like this:

$t=\frac{9.1-8}{\sqrt{\frac{(1.9)^2}{40}+\frac{(2.1)^2}{50}}}}=2.604$

Statistical decision

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

$df=n_{1}+n_{2}-2=40+50-2=88$

Since is a bilateral test the p value would be:

$p_v =2*P(t_{(88)}>2.604)=0.0108$

So the p value is a very low value and using any significance level for given $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and there is enough evidence to conclude that the two means are significantly different at 5%

3 0

3 years ago

What is the lateral area of the figure below. Use 3.14 for pi and round to

nydimaria [60]

Answer:

<em><u> $838.67mm {}^{2}$ </u></em>

Step-by-step explanation:

Note

<h2>Area of a cone = 1/3pir squared * height</h2>

4 0

3 years ago

What is the transformation of the logarithmic function from the parent log5 x?

TiliK225 [7]

Answer: Choice #3 - compressed horizontally and translated by 4 units to the right.

$g(x)=\log_5(4x-16)=\log_5 4(x-4)$

This corresponds to horizontal shift to the right by 4 units and a horizontal compression.

4 0

4 years ago

Solve the following problems:<br> Find x, y

vladimir1956 [14]

Answer:

x=1.25, y=1.75

Step-by-step explanation:

The two triangles formed (one triangle with side lengths of 5, 7, 8 and another with sides 5+x, 10, and 7+y) are similar, because they share the same angle measures.

Now, 2 sides given that we can compare ratios with are the side with length 8, and the side with length 10. 10/8= 1.25, which is the ratio of the sides on these 2 triangles.

Now we want to find what the side '5+x' is equal to. To do that we can use our ratio, and multiply 5 by 1.25 to find '5+x'. This is 6.25. To find x, all we need to do is subtract 5 from 6.25, which is 1.25.

Let's find y now. Do the same thing that we did with the side '5+x'; find what '7+y' is by multiplying 7 by 1.25, which is 8.75. 8.75-7= 1.75.

Hope this helps! :)

8 0

3 years ago

Simplify the expression. 28 + 18 ÷ 6 • (–3) 19 27 –23 –93