Step-by-step explanation
To answer this given question, we will make use of the Empirical rule of normal distribution
The Empirical Rule states that 99.7% of data observed following a normal distribution lies within 3 standard deviations of the mean. Under this rule, 68% of the data falls within one standard deviation, 95% percent within two standard deviations, and 99.7% within three standard deviations from the mean.
The image below helps gives a clearer understanding
So in our case, since the mean is 189 mg/dL and the standard deviation is 23
Then we will have the following values at