When you take an exam, it's helpful to know the average passing rate. The passing rate lists the percentage of people who pass the exam. If you subtract the passing rate from 100 percent, you have the failing rate for the exam. For example, if an exam has a 70 percent passing rate, then 70 percent of test-takers pass the exam and 30 percent fail the exam.

Determine the number of people who took the exam. For example, assume that 1,000 people take an exam.

Find the number of people who passed the exam. In the example, 700 people passed the exam.

Divide the number of people who passed the exam by the number of people who took the exam to find its pass rate. In the example, 700 divided by 1,000 equals a pass rate of 70 percent on the exam.