All categories

4 years ago

Can some one help solve this?

Mathematics

1 answer:

Zepler [3.9K]4 years ago

3 0

The easiest way to do this is to divide $5.25 from $60.25. You should get $55. Then, subtract 5.25 3 times from $55. You should get $39.25. So, their lunch costed $39.25. But, we are not done! The question says to write a equation, so we need a variable! So the real answer would be $55-$5.25-$5.25-$5.25=x. x=$39.25.Remember, don't forget your money symbol!!!!

You might be interested in

What is the distance between points (10, 7)(10, 7) and (2, 7)(2, 7) on a coordinate plane?

lawyer [7]

I am sorry i have no idea. :( But i can ask my brother who is in a higher grade than i. i will ask him when he gets home for you. :)

5 0

4 years ago

Larry plays quarterback for the Eagles. During the team's opening football game, the Eagles have the ball 48 yards away from the

frez [133]

So take 48 then subtract 31 which would equal 17. Then add back the yards they lost. So 17+19=36

6 0

3 years ago

Read 2 more answers

The fee for using a gym is $25 a year plus $3 for each visit. If someone visits v times a year, which expression represents the

Licemer1 [7]

Answer:

y=3v+25.............

6 0

3 years ago

Read 2 more answers

Ms. Larson was driving home from a vacation. At noon, she was 120 miles from home. Half an hour later, she was 98 miles from hom

melomori [17]

Answer: her speed was “44 miles per hour”

5 0

3 years ago

An automobile dealer wants to see if there is a relationship between monthly sales and the interest rate. A random sample of 4 m

SVETLANKA909090 [29]

Answer:

a) $y=-6.254 x +75.064$

b) r =-0.932

The % of variation is given by the determination coefficient given by $r^2$ and on this case $-0.932^2 =0.8687$ , so then the % of variation explained by the linear model is 86.87%.

Step-by-step explanation:

Assuming the following dataset:

Monthly Sales (Y) Interest Rate (X)

22 9.2

20 7.6

10 10.4

45 5.3

Part a

And we want a linear model on this way y=mx+b, where m represent the slope and b the intercept. In order to find the slope we have this formula:

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

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:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=278.65-\frac{32.5^2}{4}=14.5875$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=696.9-\frac{32.5*97}{4}=-91.225$

And the slope would be:

$m=\frac{-91.225}{14.5875}=-6.254$

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

$\bar x= \frac{\sum x_i}{n}=\frac{32.5}{4}=8.125$

$\bar y= \frac{\sum y_i}{n}=\frac{97}{4}=24.25$

And we can find the intercept using this:

$b=\bar y -m \bar x=24.25-(-6.254*8.125)=75.064$

So the line would be given by:

$y=-6.254 x +75.064$

Part b

For this case we need to calculate the correlation coefficient given by:

$r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

$r=\frac{4(696.9)-(32.5)(97)}{\sqrt{[4(278.65) -(32.5)^2][4(3009) -(97)^2]}}=-0.937$

So then the correlation coefficient would be r =-0.932

The % of variation is given by the determination coefficient given by $r^2$ and on this case $-0.932^2 =0.8687$ , so then the % of variation explained by the linear model is 86.87%.

6 0

3 years ago