Add all the numbers.

The mean is the average of all the numbers, which means dividing this number by five will give the average.

The answer is:  

The mean is the average of all the numbers given in the set of data.

Add all the numbers and divide by five, since there are five numbers provided.

The answer is:  

Set up an equation such that the average of Sam's four tests will equal to 90.

Solve for x.  Multiply by four on both sides.

Add the values on the left.

Subtract 240 from both sides.

Since the maximum of each test is 100, Sam cannot achieve a 90 in the class. 

The answer is:  

The mean is the average of all the numbers given in the data set.

Add the numbers.

Divide this number by five.

The answer is:  

Add all the numbers in the data set.

Divide this value by five.

The answer is:  

The mean is defined as the average of all the numbers given in the data set.

Add the numbers together.

Divide this value by four to get the mean.

The answer is:  

The mean is the sum of all terms in the data set, divided by the total amount of numbers given.

Combine like terms.

Dividing by three is similar to multiplying by one-third.

The answer is:  

The mean is the average of all the numbers given in the data set.

Sum the numbers and divide by the total amount of numbers.

Divide the two numbers.

The answer is:  

The mean is the average of all the numbers.

Add all the numbers in the data set.

Divide this number by five.

The answer is:  

Part 1: Understanding the problem

The most important part of solving this problem is to understand what is being asked. Failure to completely understand what the information states can result in an inaccurate answer.

In this problem, you are given Tony's exam scores and very important information regarding class policies. You must be aware that the lowest grade will be dropped after the final exam is complete, and not before. You must also know that all exams are weighted the same, and that is the only graded part of this course. You should make note that there is no extra credit on the exams, as the highest grade that can be achieved on any given exam is .

Learning tip: 

Feel free to cross out any irrelevant information to help you stay focused. In other words, you do not need to know that his name is Tony or that he is taking a college algebra course at Florida Atlantic University. If you do cross out any irrelevant information, you must make sure that what you are crossing out has absolutely nothing to do with what you are trying to solve. If you accidentally cross out key information, you will probably answer incorrectly.

Part 2: Determining if Tony needs to take the last exam

Step 1:

We must calculate Tony's current grade in the class to see if he even needs to take the final exam.

In other words, if his current grade is  without taking the last exam, we will know that if Tony does not take the last exam and scores , it will be dropped and Tony will still maintain a grade of . Until we find out what Tony's grade currently is, we should not drop any test scores. 

In order to find Tony's current grade, we have to take the mean (average) of all his test scores. To calculate the mean, add up all of the test scores and divide that number by the amount of tests, as shown below.

. 

Because Tony's current grade is below his standard of a , we know that we must drop the lowest test score in our calculations.

In other words, Tony must take the final exam and score very well in order to achieve a % average. After he scores well on the exam, the lowest test score () will be dropped, as the course syllabus states.

Part 3: Setting up an equation

 As we concluded from the previous parts of this problem, we will drop the lowest test score of  and add a variable representing the result of the last exam.

We will set this equal to 90, as that is Tony's desired average grade. Once we solve for x, we can find out what Tony needs on his last exam.

Now, we simplify as shown below:

Multiply  to both sides of the equation:

Subtract 354 from both sides of the equation to solve for :

Answer: Tony must achieve a score of  on his last exam in order to achieve an average score of