To help us answer this question, let's think about what we know about jobs:

If you were to get a part time job when you turn , it's likely that you'll make minimum wage because it's your first job and you haven't finished high school, nor would you have a college education. However, if you think about a doctor, graduating from medical school when he/she is about  years old, the doctor is likely going to make a lot more than minimum wage because he's gone through high school, college, and medical school. As you can probably assume, doctors make a salary much higher than minimum wage. Based on this scenario, we can conclude that as age increases, salary increases; thus, the slope of the best fit line will have a positive slope. 

We know, from attending school ourselves, that completing homework assignments and studying for quizzes and tests means that we will do better in school than if we didn't do those things. Completing homework and studying for tests takes time outside of school. Normally, the harder you study and the more time you spend studying, the more likely you are to do well in school. If you don't study at all, nor spend anytime completing homework assignments, your school grade will likely be lower than if you had spent time preparing and completing assignments; thus, we can conclude that the more time we spend studying, the higher our  will be. As the number of hours studied increases, the  will increase; thus, the best fit line will have a positive slope. 

We know, from attending school ourselves, that when we have a test coming up that we want to do well on, we'll study for the test. Normally, the harder you study and the more time you spend studying, the more likely you are to do well on the test. If you don't study at all, and don't know the material that's being covered on a test, you'll like do poorly on a test; thus, we can conclude that the more time we spend studying, the higher our test grade will be. As the number of hours studied increases, the score on the test will increase; thus, the best fit line will have a positive slope. 

The question tells us that age is the independent variable, or the , and height is the dependent variable, or the 

The  is when ; thus, when a person is just born their age is  and their average height is 

The question tells us that age is the independent variable, or the , and price is the dependent variable, or the 

The  is when ; thus, when a car is brand new its age is  and the average price is 

Imagine that you were buying a car. You have two options: a brand new car for  or the same car, but a ten year older model for , which one would you pick? Most likely, you would take the brand new car because they are the same price. As a car get's older, it decreases in value because it becomes outdated and it the car will likely have been driven a lot more miles the older it gets. This means that the slope of the best fit line will be negative, since the price will decrease as the age increases. 

Let's think about ourselves in this scenario, as you've gotten taller, has your weight increased or decreased? Most likely, as your height has increased your weight has also increased; thus the slope of the best fit line for this data would be positive.

The question tells us that the hours spent per week studying is the independent variable, or the , and the  is the dependent variable, or the 

The  is when ; thus, when a student spends zero hours studying their average  is 

The equation of the best fit line will be in slope intercept form:

The question tells us that days are the independent variable, or , and the dependent variable is the final class grade, or 

Every students starts with a . If we think about a graph, then the start of the graph is when  is equal to zero, which is the ; thus, the  value of the equation should be  

The final piece that we need is the slope, or  value, which is associated with the number of days missed. Let's recall from the question that for every single day missed the students grade dropped by . "Drops" means that we are going to have a negative slope; thus, the slope for this scenario is the following:

If we put all of the pieces together, then the equation for the line of best fit is the following:

To help answer this question, we can construct a two-way table and fill in our known quantities from the question.

The columns of the table will represent the students who have a laptop or do not have a laptop and the rows will contain the students who have a car or do not have a car. The first bit of information that we were given from the question was that  students had a laptop; therefore,  needs to go in the "laptop" column as the row total. Next, we were told that of those students,  owned a car; therefore, we need to put  in the "laptop" column and in the "car" row. Then, we were told that  students do not own a laptop, but own a car, so we need to put  in the "no laptop" column and the "car" row. Finally, we were told that  students do not have a laptop or a car, so  needs to go in the "no laptop" column and "no car" row. If done correctly, you should create a table similar to the following: 

Our question asked how many students have a laptop, but do not own have a car. We can take the total number of students that own a lap top, , and subtract the number of students who have a car, 

This means that  students who have a laptop, don't have a car.