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 #5
avatar+2441 
+1

Interesting question! I would not consider this a "simple" question. It requires one to think about it!

 

Before we attempt this problem, we have to understand how the rating system works. Generally, the rating system simply takes the average of all the responses' ratings. Therefore, we can create a formula for it.

 

\(f(\# \hspace{1mm}\text{of responses})=\frac{x_1+x_2+x_3...x_{\# \hspace{1mm}\text{of responses}}}{\# \hspace{1mm}\text{of responses}}=4.44\)

 

I will create a table, first:

 

# of responsesFormulaSolve for numerator   
2\(\frac{x_1+x_2}{2}=4.44\)\({x_1+x_2}=8.88\)   
3\(\frac{x_1+x_2+x_3}{3}=4.44\)\({x_1+x_2+x_3}=13.32\)   
4\(\frac{x_1+x_2...+x_4}{4}=4.44\)\({x_1+x_2...+x_4}=17.76\)   
5\(\frac{x_1+x_2...+x_5}{5}=4.44\)\({x_1+x_2...+x_5}=22.2\)   
6\(\frac{x_1+x_2...+x_6}{6}=4.44\)\({x_1+x_2...+x_6}=26.64\)   
7\(\frac{x_1+x_2...+x_7}{7}=4.44\)\({x_1+x_2...+x_7}=31.08\)   
8\(\frac{x_1+x_2...+x_8}{8}=4.44\)\({x_1+x_2...+x_8}=35.52\)   
9\(\frac{x_1+x_2...+x_9}{9}=4.44\)\({x_1+x_2...+x_9}=39.96\)   
10\(\frac{x_1+x_2...+x_{10}}{10}=4.44\)\({x_1+x_2...+x_{10}}=44.4\)    
n\(\frac{x_1+x_2...+x_n}{n}=4.44\)\({x_1+x_2...+x_n}=4.44n\)   

 

We have tried the first 10 responses. Will 10 responses ever give an average of 4.44? No. How do I know? We need the integers from 1 to 5 to equal a decimal number. That is impossible. Let's try the first one in the table, 2. 

 

\(x_1+x_2=8.88\)

 

If the numbers we can substitute into x are integers, it is impossible to find 2 integers that add up to 8.88 because you cannot add two integers and get a decimal. The same logic can be used for the above ones. Now we must hunt for the least number for n such that 4.44n is an integer. I have effectively changed the question now. I will use a fraction to help me out with this:

 

\(4.44\)I am going to convert 4.44 into a fraction. 4.44 extends until the hundredth place, so put it over 100.
\(4+\frac{44}{100}\)Now, I only care about the 44/100, so I will forget about the 4.
\(\frac{44}{100}\div\frac{4}{4}=\frac{11}{25}\)This fraction is irreducible. 
  

 

But what does this mean? The denominator says the least amount of response, 25. How do I know this? Well, what is 4.44*25=111. 

 

Now the last question we must ask ourselves is can we make 111 with 25 responses?
 

Yes, we can! You can have 21 5-star responses and 2 2-star responses and 2 1-star responses.

Jul 31, 2017
 #1
avatar+2441 
0

Before attempting to do this problem, you must understand the slope-intercept form of a line. It is the following:
 

\(y=mx+b\)

m = slope of the line

b = the y-intercept (the point where it touches the y-axis)

 

First, we must find the slope. To do this, we must know another formula. This will solve for m.

 

\(m=\frac{y_2-y_1}{x_2-x_1}\)

 

Now that we know the formula, let's plug the given coordinates into the formula above to determine the line's slope:

\(m=\frac{y_2-y_1}{x_2-x_1}\) Plug in the coordinate given into this formula to find the slope of the line, 
\(m=\frac{4-(-3)}{3-8}\) Remember that subtracting a negative is the same as adding a positive.
\(m=\frac{4+3}{3-8}\) Now, simplify the numerator and denominator into its simplest terms.
\(m=\frac{7}{-5}=-\frac{7}{5}\)  
   

 

We have now determined the slope of the line, -7/5. The next step is to figure out the value of b. First, let's look at the equation with the m filled in.

 

\(y=-\frac{7}{5}x+b\)

 

Just plug in a coordinate into here and solve for b. It doesn't matter which coordinate you substitute in, either. I'll use the first point, (3,4):

 

\(y=-\frac{7}{5}x+b\) Plug in the coordinate (3,4) into the equation and solve for b.
\(4=-\frac{7}{5}*3+b\) First, let's simplify the right hand side of the equation by doing -7/5*3
\(-\frac{7}{5}*3=\frac{-7}{5}*\frac{3}{1}=\frac{-21}{5}=-\frac{21}{5}\) Plug this back into the equation we were solving.
\(4=-\frac{21}{5}+b\) Multiply 5 on both sides of the equation to get rid of the pesky fractions.
\(20=-21+5b\) Add 21 to both sides of the equation.
\(41=5b\) Divide by 5 on both sides.
\(\frac{41}{5}=b\)  
   

 

Now that we have both and solved, we can write the equation in slope intercept form. 

 

\(y=mx+b\)

 

Just replace and with the numbers we calculated for both. Therefore, your final answer is:
 

\(y=-\frac{5}{7}x+\frac{41}{5}\) 

 

Here, I have supplied a link to an online graphing calculator called Desmos. It shows you that this is indeed the line that passes through both points. Here is the link: https://www.desmos.com/calculator/0tjwjbb3e7

Jul 31, 2017
 #5
avatar+2441 
0

I will end this controversy by considering both cases.

 

Case #1: If the side lengths are 1/2 inch.

 

To solve for this find the volume of the smaller cube. Finding the volume of a cube is actually simple. Just use the following formula. 

 

\(V=s^3\)

Let V = volume of the cube

Let s = side length

 

\(V=s^3\) Plug in the side length for s, ½.
\(V=(\frac{1}{2})^3\) "Distribute" the cube into both the numerator and denominator.
\(V=\frac{1^3}{2^3}\)  
\(V=\frac{1}{2*2*2}=\frac{1}{8}\) Ok, the volume of the cube is 1/8in^3.
   

 

To find how many of cubes with a volume of 1/8in^3 would fit in a 96in^3 rectangular prism, just divide them.

 

\(\frac{V_{rect.}}{V_{cube}}\)

 

Let's do that!

 

\(\frac{V_{rect.}}{V_{cube}}\) Just plug in the values are solve from there.
\(\frac{96}{\frac{1}{8}}\) We will use a fraction rule that states that \(\frac{a}{\frac{b}{c}}=\frac{a*c}{b}\)
\(\frac{96}{\frac{1}{8}}=\frac{96*8}{1}=768\)  
   

 

Therefore, \(768\) cubes with a length of 1/2in can fit in a rectangular prism with a volume of 96in^3.

 

Case #2: If the cube has a volume of 1/2in^3

 

We already know the volume of both cubes, so divide the rectangular prism's volume from the cube's volume:

 

\(\frac{96}{\frac{1}{2}}\) I will utilize a fraction rule that states that \(\frac{a}{\frac{b}{c}}=\frac{a*c}{b}\)
\(\frac{96}{\frac{1}{2}}=\frac{96*2}{1}=192\)  
   


In this scenario, \(192\) cubes of a volume of 1/2in^3 can fit in a rectangular prism with a volume of 96in^3.

Jul 31, 2017

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