All ACT Math Resources
Example Questions
Example Question #44 : How To Find Arithmetic Mean
Find the arithmetic mean of this set of data:
{0, 0, 0, 0, 1, 5}
1
3
0
4
5
1
The sum of all the terms is 6. The number of terms in the set is 6. 6/6 = 1
Example Question #43 : Statistics
Greg got an average of 93 on his test scores this semester. He got a 92, 93, and 97 on the first three tests. If he received the same score on each of his last three tests, what was his score on each of these tests?
90.5
92.33
89
92
94
92
We can set up an equation (92 + 93 + 97 + 3x)/6 = 93. Solving for x yields 92.
Example Question #45 : Arithmetic Mean
Tom needs an average test score of 75 to pass his math class. The class gives five equally-weighted tests, and his first four scores were 57, 63, 90, and 72. What score does he need to receive on his final test to pass his class?
The formula for the average of Tom's scores is
He needs an average of 75, so his average is represented by the following formula where "" represents his fifth test score.
Multiply the five across:
Subtracting:
Example Question #2 : How To Find Excluded Values
If the average (arithmetic mean) of , , and is , what is the average of , , and ?
There is not enough information to determine the answer.
If we can find the sum of , , and 10, we can determine their average. There is not enough information to solve for or individually, but we can find their sum, .
Write out the average formula for the original three quantities. Remember, adding together and dividing by the number of quantities gives the average:
Isolate :
Write out the average formula for the new three quantities:
Combine the integers in the numerator:
Replace with 27:
Example Question #51 : Statistics
What is the mean of the values of for values of between and ?
For this, you need to calculate for each of your values:
The mean of these numbers is merely:
Example Question #51 : How To Find Arithmetic Mean
Henry is taller than Barbara, who is shorter than Lisa. If Lisa is tall, what is the mean height of this group?
Based on our information, we know the following values for the individuals’ heights:
Lisa: inches
Barbara: inches
Henry: inches
Thus, the mean height for this group is:
Example Question #52 : Statistics
In a class of students, took an exam on Wednesday. Based on these students, the average score was . If the last two students scored a and a , what was the average score for the whole class?
To compute this, you need first to compute the total points earned by the first group of students. This would be:
Now, you need to add in the scores of the two new students:
To compute the new average, you need to divide this value by :
Example Question #51 : How To Find Arithmetic Mean
A basketball player in the 2015 NBA finals scored the following point totals over 6 games:
44, 39, 40, 20, 40, and 32. What was his mean points per game? (Round to the nearest tenth)
To find the mean, sum all the numbers and divide by the total amount of numbers.
Example Question #52 : How To Find Arithmetic Mean
The following is a list of test scores received by one student on her last 7 tests:
92, 91, 84, 72, 88, 95, 96. What is her average test score? Round your answer to the nearest tenth.
To find the average of a given data set, sum the totals and divide by the total number of numbers in your data set.
Example Question #53 : How To Find Arithmetic Mean
A student runs a mile around the track and his coach takes record of each lap's time. His times were as follows in seconds:
.
Using this data, find the student's mean lap time.
To find the arithmetic mean, you simply add up all of the data and divide by the number of data points there are.
In this case there are 4 data points.
.