Because if you study you would most likely know what the test/quiz/exam is about and understand the problems. If you don't study then you would probably not know how to do the work or solve the problems on the quiz/test/exam. (very sorry if wrong!)
The sale price is out of the original price so do 424.15 / 499.00 to find what it is out of in decimal form. Multiply your answer by 100 to find the percentage.
