The systolic blood pressure of a group of 18-year-old women is normally distributed with a mean of 112 mmhg and a standard deviation of 11 mmhg. what percentage of 18-year-old women in this group have a systolic blood pressure that lies within 3 standard deviations to either side of the mean?

By the empirical rule, 99.7 percent of all values in a normal distribution lie within 3 standard deviations of the mean. Since the population is normally distributed, the percentage that lies within 3 standard deviations of the mean is 99.7 percent.

Alternatively, you can use a z-score table to look up the area between - infinity and - 3 to get the percentage that lies below 3 standard deviations below the mean, and the rest of the calculations should be trivial.