The mean systolic blood pressure of adult males is normally distributed with a mean of 138 (millimeters of mercury) and a standard deviation of 9.7. What percent of adult males have blood pressure between 161.28 and 164.9?

That is a pretty narrow range of systolic pressure, far above the mean. Use a normal distribution table or Java computation tool, such as the one at

http://psych.colorado.edu/~mcclella/java/normal/accurateNormal.html

I get 0.54%