Question

Like the average atomic masses reported on the periodic table, grades are often determined using weighted averages. Let's say that the grade in a chemistry course is based 65% on exams, 22% on online homework, 3% on lecture clicker responses, and 10% on recitation. Using a weighted average, help your friend calculate her current grade in the class if her scores are as follows: 65.9% on exams, 80.6% on homework, 95.2% on clickers, and 79.5% in recitation.

a) 71.4%
b) 85.0%
c) 75.3%
d) 88.5%

Answer 1

To find the weighted average grade, multiply each score by its weight and sum the results. Your friend's weighted average grade in the chemistry course is approximately 71.4%, corresponding to answer choice (a).

Step-by-step explanation:

To calculate your friend's current grade in the chemistry course using a weighted average, you multiply each component of the grade by its respective weight, then sum these values. Here's the calculation based on the provided scores:

• Exams: 65.9% × 65% = 42.835%
• Homework: 80.6% × 22% = 17.732%
• Clickers: 95.2% × 3% = 2.856%
• Recitation: 79.5% × 10% = 7.95%

Add these together to get the total:

42.835% + 17.732% + 2.856% + 7.95% = 71.373%

After rounding, your friend's current grade in the class would be approximately 71.4%, which corresponds to answer choice (a).

Always remember to check that the sum of the weights equals 100% and that the calculated grade makes sense based on the input values.