|
|
|
Weighted Averages
Your grade is determined by a weighted average of your homework grades, your quiz grades and your test grades. Your teacher assigns a weight of 1 to you homework grade, a weight of 2 to your quiz grades, and a weight of 5 to your test grades. If your homework grade is 95, and your quiz grade is 90, and your test grade is 85, then your weighted average is calculated as:
A weighted average is the sum of the product of the number of units (the weight) and the value per unit divided by the sum of the units (weights).
Weighted averages can be used to solve a mixture problem in which two or more parts are combined into a whole.
Your class is going to sell fruit baskets. They want to keep the cost at $9.95 per pound. You are going to include 2 pounds of apples at $2.75 per pound, 1.5 pounds of bananas at $1.50 per pound. If oranges sell for $2.25 per pound, how many pounds of oranges can you include in the basket
(2 x 2.75) + (1.5 x 1.50) + (n x 2.25) = (1 + 1.5 + n) x 9.95
5.5 + 2.25 + 2.25n = 9.95 + 14.925 + 9.95n
7.7n = 17.125
n = 2.22 pounds of oranges
|
|
|
