Convert to the standard normal distribution then read the values off your tables.
The reading speed of a sixth grade student is normally distributed with a mean speed of 125 words per minute and a standard deviation of 24 words per minute.
a) what is the probability that a randomly selected sixth grade student reads less than 100 words per minute?
b) what is the probability that a randomly selected student reads more than 140 words per minute?
c) between 100 and 140 words per minute?