1. Averages
Record your work and answers on a piece of paper.
These practice problems are due at the end of the period.No late work will be accepted.
To complete this lesson, put on headphones and view as a full-screen slideshow.
Pause button

2. Find the average:
1. Add all values.
2. Divide by the number of values.
Example:
Find the average of the following set of values:
89, 66, 98, 75, 96, 86
Show your work on paper:
Find the average of the following set of values:
1. 12, 14, 22
2. 61, 71, 74, 89, 90
3. 40, 55, 56, 59, 64, 74
4. 110, 152
89 + 66 + 98 + 75 + 96 + 86 = 510
510 / 6 = 85
because there were 6 values
3. Basic Average Word Problems
5. The daily totals of lunch customers served at the Sunshine Caf last Monday through Saturday were 256, 189, 204, 179, 166, and 218.What was the average number of lunch customers served each day?
A. 1,212
B. 256
C. 202
D. 197
E. 173
6. A group of friends were comparing the number of cards in their baseball card collection.The number of cards is indicated in the table below.
Friend A BCDE
Cards301107020070
What is the average number of baseball cards in the collection of the 5 friends?
A. 70
B. 82
C. 96
D. 102.5
E. 120
7. As part of a school report on the cost of gasoline, Raquel wants to find the average cost of purchasing a gallon of regular unleaded gasoline from local gas stations.She surveys 4 stations and finds the cost per gallon of regular unleaded gas from he 4 stations to be $2.45, $2.50, $2.49, and $2.56, respectively.Using this data, what is the average cost of purchasing one gallon of regular unleaded gasoline from these 4 gas stations?
A. $2.55
B. $2.53
C. $2.50
D. $2.49
E. $2.45
4. Find the average from part of the data:
1. Figure out which data to use.
2. Find the average.
Example:
Geoff made the following scores in a game: 12, 13, 15, 9, 10, 15, 11, 15, 18, 29, 8.The highest score and lowest score are not counted in the set.What is the average of the set without the highest score and lowest score?
Show your work on paper:
Find the average of the following set of values excluding the highest number:
8. 68, 37, 54, 71, 45
9. 19, 21, 25, 17
10. 82, 95, 66, 59, 84, 74
8, 9, 10, 11, 12, 13, 15, 15, 15, 18, 29
9 + 10 + 11 + 12 + 13 + 15 + 15+ 15 + 18 = 118
118 / 9 = 13
5. Find the average from part of the data problems
11. Mr. Polk does no count the highest and lowest scores when determining a students final grade.A student has the following set of scores: 70, 87, 80, 86, 88, 93, 84.If Mr. Polk does not include the highest and lowest scores, what is the average score for the set?
A. 84
B. 85
C. 86
D. 87
E. 88
12. To determine a students overall test score for the semester, Ms. Lopez throws out the lowest test score and takes the average of the remaining test scores.Victor earned the following test scores in Ms. Lopezs class this semester: 62, 78, 83, 84, and 93.What overall test score did Victor earn in Ms. Lopezs class this semester?
A.67.6
B. 80.0
C. 83.0
D. 83.5
E. 84.5
6. Find a missing value:
1. Calculate the number all the numbers should add up to.
2. Subtract to find the missing value.
Example:
The average of 3 numbers is 45.If 2 of the numbers are 35 and 45, what is the third number?
Show your work on paper:
Find the missing value in each set:
13. 5, 10, ___.
Average = 9
14. 20, 24, 29, ___.
Average = 21
15. 43, 45, 56, 59, 64, ___
Average = 50
35, 45, ____
Average: 45
45 * 3 = 135
because there were 3 values
135 35 = 100 45 = 55
7. Find a Missing Value Problems
16. If the average of a and -5 is 10, then a=
A. 25
B. 15
C. 5
D. -5
E. -15
17. George has taken 5 tests in math class and scored 98, 78, 87, 99, and 83.If each math test has 100 points possible, what is the lowest score George can receive on the next test to have at least a 92 average?
A. 89
B. 92
C. 95
D. 100
E. George cannot average 92 on the 6 tests.
18. Zoe bought three fish at the pet store. Two of the fish were $7.00 each. If the average cost of the three
fish was $9.00, how much was the third fish?
A. $7.00
B. $7.67
C. $9.00
D. $13.00
E. $16.00
19. A student has earned the following scores on four 100-point tests this marking period: 63, 72, 88, and 91.What score must the student earn on the fifth and final 100-point test of the marking period to earn an average test grade of 80 for the five tests?
A. 79
B. 86
C. 89
D. 94
E. The student cannot earn an average of 80.
20. In a certain course, Lily received an average score of 82 for her first 2 tests, 76 for her third test, and 92 for her fourth test.What grade must she receive on her next test if she wants an average of 86 for all 5 tests?
A. 92
B. 94
C. 96
D. 98
E. 100
8. Find the average of algebraic terms:
1. Add all values by combining like terms.
2. Divide everything by the number of values.
Example:
What is the average of n, n + 1, n + 2, and n + 3?
Show your work on paper:
Find the average of the following set of values:
21. k + 1, k + 3, k + 5
22. 2m, 3m, 4m, 7m, 9m
n + n + 1 + n + 2 + n + 3 = 4n + 6
(4n + 6) / 4 = 1n + 1.5
because there were 4 values
9. Average of Algebraic Terms
23. What is the average of
3x + 2, 4x + 1, and 2x?
2x
3x
3x + 1
3x + 2
9x + 3
24. If the average of x + 2, x + 4, and x + 6is 0, then x =
-4
-3
-2
-1
0
10. Problems with changing averages:
1. Create an easy set of numbers that works.
2. Change the numbers according to the problem.
Example:
The average of 6 numbers is 6.If 3 is subtracted from each of 4 of the numbers, what is the new average?
6, 6, 6, 6, 6, 6
3, 3, 3, 3, 6, 6
3 + 3 + 3 + 3 + 6 + 6= 24
24 / 6 = 4
11. Problems with Changing Averages
25. The average of 8 numbers is 10.If 4 is added to 5 of the numbers, what is the new average?
9
10
12
14
15
26. The average of 3 numbers is 21.If 9 is subtracted from one of the numbers, what is the new average?
9
12
18
21
24
12. Congratulations!
Youre Done!