Problem 1: The average of five numbers is 88. Four of the numbers are 100, 80, 75, and 89. What is the fifth number? Problem 2: Jose scored an average of 20 points in each of four games. Altogether, what was the total number of points that he scored for all four games? Problem 3: Mei's average score on the first six holes in a miniature golf game was 6. Her average score on the next 12 holes was 3. What was her average score on all 18 holes?

1. Problem Description

Problem 1: The average of five numbers is

8

8. Four of the numbers are 100, 80, 75, and

8

9. What is the fifth number?

Problem 2: Jose scored an average of 20 points in each of four games. Altogether, what was the total number of points that he scored for all four games?

Problem 3: Mei's average score on the first six holes in a miniature golf game was

6. Her average score on the next 12 holes was

3. What was her average score on all 18 holes?

2. Solution Steps

Problem 1:

Let the five numbers be $a, b, c, d,$ and $e$. We are given that the average of these five numbers is 88, so:

$\frac{a+b+c+d+e}{5} = 88$.

We are given four of the numbers are 100, 80, 75, and

8

9. Let $a=100, b=80, c=75, d=89$. Then we want to find $e$.

$\frac{100+80+75+89+e}{5} = 88$

$100+80+75+89+e = 88 \times 5$

$344 + e = 440$

$e = 440 - 344$

$e = 96$

Problem 2:

Jose scored an average of 20 points in each of four games.

To find the total number of points, multiply the average points per game by the number of games:

Total points = average points $\times$ number of games

Total points = $20 \times 4 = 80$

Problem 3:

Mei's average score on the first six holes was

6. Her average score on the next 12 holes was

3. Total score on the first six holes: $6 \times 6 = 36$

Total score on the next 12 holes: $3 \times 12 = 36$

Total score on all 18 holes: $36 + 36 = 72$

Average score on all 18 holes: $\frac{72}{18} = 4$

3. Final Answer

Problem 1: 96

Problem 2: 80

Problem 3: 4