In order to determine whether Sally will qualify for the last time trial, set up an equation to find the mean.  Out of the five scores, one of the scores is unknown, and Sally's final score must be  or higher.  Let the unknown score be .  

Write the equation to solve for the mean.

Unfortunately, Sally cannot make the gymnastics team because she needs to earn a 10.8, which is not possible on the score limit.

The correct answer is:

The mean is also the average of a set of numbers. To find the mean, add all of the numbers in the set:  , , , , , and . Then, divide your answer by the number of terms present within the set, in this case .

In this case, the sum of all the numbers is . Divide by the size of the set: .

This will give you an average or mean of .

To get the total combined score of everyone in the class, multiply the average of the class by the number of students.

. Since the teacher decided to drop the lowest 2 scores, let's subtract those 2 scores from the total.

.

Now the new total is 697. To find the new average, divide this new total by the new number of grades to be averaged in, which is 8. Remember that the teacher dropped 2 grades so there are less grades to take into account.

To find the mean, there are two steps:

1. Add all of the numbers in the set together.

2. Divide that number by the amount of numbers are in the set.

For this problem there are ten numbers so we add them up and divide by ten:

To find the mean, there are two steps:

1. Add all of the numbers in the set together.

2. Divide that number by the amount of numbers are in the set.

For this problem there are 16 numbers in the set, so we add the numbers together and divide by 16 to find the mean:

To find the mean, there are two steps:

1. Add all of the numbers in the set together.

2. Divide that number by the amount of numbers are in the set.

For this problem there are 11 numbers in the set, so we add the numbers together and divide by 11 to find the mean:

To find the mean, there are two steps:

1. Add all of the numbers in the set together.

2. Divide that number by the amount of numbers are in the set.

For this problem there are 16 numbers in the set, so we add the numbers together and divide by 16 to find the mean:

To find the mean, there are two steps:

1. Add all of the numbers in the set together.

2. Divide that number by the amount of numbers are in the set.

For this problem there are 12 numbers in the set, so we add the numbers together and divide by 12 to find the mean:

To find the mean, there are two steps:

1. Add all of the numbers in the set together.

2. Divide that number by the amount of numbers are in the set.

For this problem there are 13 numbers in the set, so we add the numbers together and divide by 13 to find the mean:

To find the mean, there are two steps:

1. Add all of the numbers in the set together.

2. Divide that number by the amount of numbers are in the set.

For this problem there are 7 numbers in the set, so we add the numbers together and divide by 7 to find the mean: