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Rina8888 [55]
4 years ago
5

Two Submarines starting from the same point cruise for two hours, one

Mathematics
1 answer:
Aleksandr [31]4 years ago
5 0

Answer:

2 hour

Step-by-step explanation:

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At 8:00 A.M., Jackie starts at the north end of a 10-mile trail and begins walking south at an average speed of 2 mph. After a w
Tcecarenko [31]

Answer:

  • 3.08 miles

Step-by-step explanation:

  • Total distance = 10 miles
  • Total time = 2 hours
  • Distance walked = x
  • Speed walked = 2 mph
  • Distance cycled = 10 - x
  • Speed cycled = 15 mph

<u>Using the given data we can have the equation below to the time:</u>

  • x/2 + (10 - x)/15 = 2
  • 30x/2 + 30(10 - x)/15 = 30(2)
  • 15x + 20 - 2x = 60
  • 13x = 60 - 20
  • 13x = 40
  • x = 40/13
  • x = 3.08 miles <em>rounded to 2 decimal places</em>
7 0
3 years ago
The national mean annual salary for a school administrator is $90,00 a year (The Cincinnati Enquirer, April 7, 2012). A school o
timurjin [86]

Answer:

a) Null hypothesis:\mu = 90000  

Alternative hypothesis:\mu \neq 90000  

b) p_v =2*P(t_{(24)}  

c) If we compare the p value and the significance level given \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean for the salary differs from 9000 at 5% of significance.

Step-by-step explanation:

1) Data given and notation  

77600 ,76000 ,90700 ,97200 ,90700 ,101800 ,78700 ,81300 ,84200 ,97600 ,

77500 ,75700 ,89400 ,84300 ,78700 ,84600 ,87700 ,103400 ,83800 ,101300

94700 ,69200 ,95400 ,61500 ,68800

We can calculate the sample mean and deviation with the following formulas:

\bar X =\frac{\sum_{i=1}^n X_i}{n}

s=\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}

The values obtained are:

\bar X=85272 represent the mean annual salary for the sample  

s=11039.23 represent the sample standard deviation for the sample  

n=25 sample size  

\mu_o =90000 represent the value that we want to test

\alpha=0.05 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)  

Part a: State the null and alternative hypotheses.  

We need to conduct a hypothesis in order to check if the mean salary differs from 90000, the system of hypothesis would be:  

Null hypothesis:\mu = 90000  

Alternative hypothesis:\mu \neq 90000  

If we analyze the size for the sample is < 30 and 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".  

Part b: Calculate the statistic

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

t=\frac{85272-90000}{\frac{11039.23}{\sqrt{25}}}=-2.141    

P-value

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

df=n-1=25-1=24  

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

p_v =2*P(t_{(24)}  

Part c: Conclusion  

If we compare the p value and the significance level given \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean for the salary differs from 9000 at 5% of significance.

6 0
3 years ago
The dimensions (width and length) of room1 have been read into two variables: width1 and length1. the dimensions of room2 have b
Reika [66]
Hello : 
<span>a single expression  is : A = xy +zk
x : </span> width1       y : <span>length1
z : </span>width2        k : <span>length2
A : </span><span>the total area of the two rooms
note : 
A1 = xy  ........</span>area of the room 1<span>
A2 = zk   </span>.......area of the room 2
3 0
3 years ago
A soccer team made 76 penalty shots out of 100.Which ratio represents successful penalty shots to missed penalty shots?
almond37 [142]
Sense we are wanting to find <u>how many were miss</u>, then, we are practically going to subtract the following:

\boxed{76-100}= \     \left[\begin{array}{ccc}\bf{24\end{array}\right]

So, from this begin understood, we would then combine both the penalties that were shotted, to the onces that weren't.

So, b subtracting these both, we would grab the result, and then smash that with the number of the penalties that were made in.

Your answer: \boxed{\bf{76:24}}
5 0
3 years ago
How many solutions can be found for the equation 4z 2(z − 4) = 3z 11? none one two infinitely many
Rus_ich [418]

There is only one solution for the equation 4z + 2(z -4) = 3z + 11 because the exponent for the power of z is 1.

<h3>What is an equation?</h3>

In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign =.

<h3>What is the Solution?</h3>

A solution is any value of a variable that makes the specified equation true.

According to the given information:

4z + 2(z-4)= 3z+11

Solve the equation,

4z+2z-8=3z+11

6z-3z=11+8

3z =19

z=

Hence,

Number of solution that can be found for the equation 4z + 2(z-4)= 3z+11 is option(2) one

To know more about Equations and Solutions visit:

brainly.com/question/545403

#SPJ4

8 0
2 years ago
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