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sergeinik [125]
3 years ago
11

Mark is six years older than his brother Sam. The sum of their ages is 30. Let a be Sam's age. Set up and solve an equation usin

g the information given to find the value of a.
Mathematics
1 answer:
Vadim26 [7]3 years ago
5 0

Answer:

a = 12 years

Step-by-step explanation:

Mark is 6 years older than his brother Sam. Now, we are asked to represent Sam’s age by a. This means that if Sam is a years old, Mark is (a + 6) years old.

The sum of their ages is 30, this means that when we add their ages together, we get the sum of thirty.

Mathematically this means a + a + 6 = 30

2a + 6 = 30

This is the equation needed to get a. To get a , we proceed to solve the equation to completion.

2a = 30 - 6

2a = 24

a = 24/2

a = 12

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Sonja [21]

Answer:

x=-6

Step-by-step explanation:

So we have the equation:

-34=7(x+8)+8x

First, distribute the 7 into the (x+8) and simplify:

-34=7(x)+7(8)+8x\\-34=7x+56+8x

Combine the like terms 7x and 8x by adding them together:

-34=56+15x

Subtract 56 from both sides to isolate the x:

-34-56=15x+56-56\\15x=-90

Divide both sides by 15 to get x:

x=-90/15=-6

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3 years ago
(x+1) - 4<br><br>How do i determine the roots ​
irga5000 [103]
<h2><u>Solution</u>:</h2>

<em>To find the zero,</em>

<em>x</em> + 1 - 4 = 0

<em>x</em> = 4 - 1

<em>x</em> = 3

3 is the <u>root</u> of <em>(x + 1) - 4</em>.

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3 years ago
A sample of 100 workers located in Atlanta has an average daily work time of 6.5 hours with a standard deviation of 0.5 hours. A
Readme [11.4K]

Answer:

t=\frac{6.5-6.7}{\sqrt{\frac{0.5^2}{100}+\frac{0.7^2}{110}}}}=-2.398  

df = n_1 +n_2 -2= 100+110-2= 208

Since is a bilateral test the p value would be:

p_v =2*P(t_{208}

Comparing the p value with the significance level given \alpha=0.05 we see that p_v so we can conclude that we can reject the null hypothesis, and we have significant differences between the two groups at 5% of significance.

Step-by-step explanation:

Data given and notation

\bar X_{1}=6.5 represent the sample mean for Atlanta

\bar X_{2}=6.7 represent the sample mean for Chicago

s_{1}=0.5 represent the sample deviation for Atlanta

s_{2}=0.7 represent the sample standard deviation for Chicago

n_{1}=100 sample size for the group Atlanta

n_{2}=110 sample size for the group Chicago

t would represent the statistic (variable of interest)

\alpha=0.01 significance level provided

Develop the null and alternative hypotheses for this study?

We need to conduct a hypothesis in order to check if the meanfor atlanta is different from the mean of Chicago, the system of hypothesis would be:

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

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

Since we don't know the population deviations for each group, 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 value of the test statistic for this hypothesis testing.

Since we have all the values we can replace in formula (1) like this:

t=\frac{6.5-6.7}{\sqrt{\frac{0.5^2}{100}+\frac{0.7^2}{110}}}}=-2.398  

What is the p-value for this hypothesis test?

The degrees of freedom are given by:

df = n_1 +n_2 -2= 100+110-2= 208

Since is a bilateral test the p value would be:

p_v =2*P(t_{208}

Based on the p-value, what is your conclusion?

Comparing the p value with the significance level given \alpha=0.05 we see that p_v so we can conclude that we can reject the null hypothesis, and we have significant differences between the two groups at 5% of significance.

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Dennis_Churaev [7]
You need to convert it into a whole number
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Answer:

-1 is your answer.

Step-by-step explanation:

What you do is the slope formula.

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-8/8 =

-1 is your answer.

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