Finding % from a standard deviation problem

Question

The average score on SAT math was 500 with a standard deviation of 100. What is the % of persons having math scores between 500 & 650

Answer 1

I am assuming that the Math scores are normally distributed. ie. X~Normal (mean=500, sd=100)

Then calculate the probability-- P( 500 < X < 650) and convert to %.

From: http://onlinestatbook.com/2/calculators/normal_dist.html

Answer is approximately 43.32%