Answer:
B.
About 16% of the books have fewer than 150 pages.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 180, standard deviation = 30.
150 pages:
150 is 180 - 30 = 1 standard deviation below the mean.
We have that approximately 68% of measures are within 1 standard deviation of the mean, so 100 - 68 = 32% are more than one standard deviation.
The normal distribution is symmetric, which means that of those 32%, 32/2 = 16% are more than 1 standard deviation below the mean, that is, below 150.
So the correct answer is given by option B.
