Lets say that this number is . If we follow what the question is saying, we come up with the equation:

We will divide both sides by 4 to isolate  on the left side.

So,

We simplify:

For simplicity, let's call our years , , and , with  being the amount of snow it snowed two years ago,  being the amount of snow it snowed last year, and  being the amount of snow it snowed this year. Now, we know that year  is .  Based on this, we can say that  is .  Finally, we know that year year  could be written:

Based on our data, this is:

Every second, you know that Marge and William will become a total of  or .  Now, you can use the simple work formula for distance:

 or, for our data, 

(Remember  kilometers is  meters.)

Thus, solving for  you get:

This is in seconds, though. You need minutes. To convert, you need to divide by :

Slope-intercept form is written as .

There is only one answer choice in this form:

The slope-intercept form of a line is: , where  is the slope and is the y intercept.

Below are the steps to get the equation into slope-intercept form.

First, we need to find the slope of the above line. 

Given two points, , the slope can be calculated using the following formula:

Set :

Second, we note that the -intercept is the point . 

Therefore, in the slope-intercept form of a line, we can set  and :

There are two ways that you can find the y-intercept for an equation.  You could substitute  in for .  This would give you:

Simplifying, you get:

However, another way to do this is by finding the slope-intercept form of the line.  You do this by solving for :

Just divide everything by :

Remember that the slope-intercept form gives you the intercept as the final constant.  Hence, it is  as well!

There are two ways that you can find the y-intercept for an equation.  You could substitute  in for .  This would give you:

Simplifying, you get:

However, another way to do this is by finding the slope-intercept form of the line.  You do this by solving for .  Indeed, this is very, very easy.  Recall that the slope intercept form is:

This means that, as written, your equation obviously has .  You don't even have to do all of the simplification!

In order to figure this out, you should use your slope-intercept formula.  Remember that the y-intercept is the place where  is zero.  Therefore, the point  gives you your y-intercept.  It is .  Now, to find the slope, recall the slope equation, namely:

For your points, this would be:

This is your slope.

Now, recall that the point-slope form of an equation is:

, where  is your slope and  is your y-intercept

Thus, your equation will be:

In order to compute the slope of a line, there are several tools you can use.  For this question, try to use the slope-intercept form of a line.  Once you get the equation into this form, you basically can "read off" the slope right from the equation!  Recall that the slope-intercept form of an equation is:

Now, looking at each of your options, you know that you can eliminate two immediately, as their slopes obviously are not :

The next is almost as easy:

When you solve for , your coefficient value for  is definitely not equal to :

Next,  is not correct either.  When you start to solve, you should notice that  will always have a negative coefficient.  This means that it certainly will not become  when you finish out the simplification.

Thus, the correct answer is:

Really, all you have to pay attention to is the  term.  First, you will subtract  from both sides:

Then, just divide by , and you will have !