€ Practice

Rob is saving to buy an MP3 player. For every 15 dollars he earns babysitting, he saves 6 dollars. On Saturday rob earned $75 do

zhenek [66]

Answer:

Rob saved $30 while he earned $75.

Step-by-step explanation:

Given:

For every 15 dollars he earns babysitting, he saves 6 dollars.

For money earned = $15

Money saved = $6

We will first find the percentage amount saved by rob

Percentage of amount is calculated by dividing money saved with for money saved and then multiplied by 100.

Percentage amount saved = $\frac{6}{15}\times100 =40\%$

Now we need to find the amount of money save when money earned $75.

Amount of money saved can be calculate by multiplying money earned with percentile amount saved.

Framing in equation form we get;

Amount saved = $\frac{40}{100}\times75 =\$30$

Hence Rob saved $30 while he earned $75.

6 0

3 years ago

In order for a company's employees to work in a foreign office, they must take a test in the language of the country where they

ArbitrLikvidat [17]

Answer:

$\sum x= 37, \sum y= 672, \sum xy =2907, \sum x^2 =173, \sum y^2 = 51320$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=173-\frac{37^2}{9}=20.889$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=2907-\frac{37*672}{9}=144.333$

And the slope would be:

$m=\frac{144.333}{20.889}=6.90953$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{37}{9}=4.111$

$\bar y= \frac{\sum y_i}{n}=\frac{672}{9}=74.667$

And we can find the intercept using this:

$b=\bar y -m \bar x=74.667-(6.9096*4.111)=46.241$

So the line would be given by:

$y=6.9096 x +46.241$

And for this case the value of the slope m = 6.9096 means that for every increase of 1 unit in the number of years we have an increase of approximately 6.9096 in the grades of the test.

Step-by-step explanation:

Data given:

x: 3, 4, 4, 5, 3, 6, 2, 7, 3

y: 61, 68, 75, 82, 73, 90, 58, 93, 72

$m=\frac{S_{xy}}{S_{xx}}$