The grades on the last math exam had a mean of 72%. Assume the population of grades on math exams is known to be distributed normally, with a standard deviation of 5%. Approximately what percent of students earn a score between 72% and 87%?

Question

anonymous · Answer

Answer Choices: 
49.9%
1%
50%
47.7%

anonymous · Answer

@Hero @ganeshie8 @dan815 @Michele_Laino @nincompoop

anonymous · Answer

I mostly confused on which formula to use for this kind of question...