To calculate a weighted average, use the formula:

[tex]\[ \text{weighted average} = \frac{\sum x w}{\sum w} \][/tex]

where [tex]\( w \)[/tex] is the weight of the piece of data [tex]\( x \)[/tex], [tex]\(\sum x w\)[/tex] is the sum of the products of each piece of data multiplied by its weight, and [tex]\(\sum w\)[/tex] is the sum of the weights.

Suppose that your final grade for a course is determined by a midterm exam and a final exam. The midterm exam is worth 45% of your grade, and the final exam is worth 55%. If your midterm grade is 95 and your final exam grade is 75, calculate your final weighted average.

Your final weighted average is [tex]\(\square\)[/tex] (Round to the nearest integer as needed).



Answer :

To calculate your final weighted average, we'll use the formula for the weighted average, which is:

[tex]\[ \text{Weighted Average} = \frac{\sum (x \cdot w)}{\sum w} \][/tex]

where:
- [tex]\( x \)[/tex] represents each individual grade,
- [tex]\( w \)[/tex] represents the corresponding weight for each grade,
- [tex]\(\sum (x \cdot w)\)[/tex] is the sum of the products of each grade and its respective weight,
- [tex]\(\sum w\)[/tex] is the sum of the weights.

In this problem:
- Your midterm exam grade [tex]\( x_1 \)[/tex] is 95, and its weight [tex]\( w_1 \)[/tex] is 45% or 0.45.
- Your final exam grade [tex]\( x_2 \)[/tex] is 75, and its weight [tex]\( w_2 \)[/tex] is 55% or 0.55.

Using the formula, we can compute the weighted average step-by-step:

1. Calculate the product of each grade and its respective weight:
[tex]\[ x_1 \cdot w_1 = 95 \cdot 0.45 = 42.75 \][/tex]
[tex]\[ x_2 \cdot w_2 = 75 \cdot 0.55 = 41.25 \][/tex]

2. Sum these products:
[tex]\[ \sum (x \cdot w) = 42.75 + 41.25 = 84.0 \][/tex]

3. Sum the weights (in this case, the weights should sum to 1 since they represent percentages that add up to 100%):
[tex]\[ \sum w = 0.45 + 0.55 = 1.0 \][/tex]

4. Apply the weighted average formula:
[tex]\[ \text{Weighted Average} = \frac{84.0}{1.0} = 84.0 \][/tex]

5. To find the final rounded weighted average, round 84.0 to the nearest integer. Hence, the rounded weighted average is 84.

Therefore, your final weighted average is [tex]\( 84 \)[/tex].