From the information given, she made an 80 the first week she took the quiz, then the next week she made a 76. Furthermore, we are asked to find the percent decrease.
Decrease means less. And less means subtraction in terms of Mathematics. So, hence, subtract 76 from 80 to find the percent decrease.
80 - 76 = 4
Now, just add the percentage behind the result.
4%
Therefore, the percent decrease in Besty's score is 4%.
