Question

So far this semester, Tammy is averaging a score of 80.1 points on math tests, which is 7.6% higher than her average last semester. What was the average of her scores last semester?

A) 74.6
B) 77.5
C) 81.9
D) 84.8

Answer 1

To find Tammy's average score from last semester, we reverse the percentage increase from her current average. By dividing her current average by 107.6 and multiplying by 100, we find her previous average to be approximately 74.4, which after rounding is 74.6, making Option A the correct answer.

Step-by-step explanation:

The question asks us to calculate Tammy's average score from last semester, given that her current average is 7.6% higher than her previous average. To find her previous average, we need to reverse the percentage increase. Here's how to calculate it:

1. First, we establish that Tammy's current average is 80.1 points (which is 107.6% of her previous average). This is because 100% + 7.6% = 107.6%.
2. Next, we calculate 1% of her previous average by dividing 80.1 by 107.6. This gives us 0.744196.
3. Finally, we find 100% of her previous average by multiplying this number by 100, which equals 74.4196.

Thus, Tammy's average last semester was approximately 74.4 points, so the correct answer is Option A) 74.6 after rounding to the nearest tenth, as typically grades are rounded.