An office manager has received a report from a consultant that includes a section on equipment

replacement. The report indicates that scanners have a service life that is normally distributed

with a mean of 41 months and a standard deviation of 4 months. On the basis of this information,

determine the percentage of scanners that can be expected to fail in the following time periods:

a. Before 38 months of service

b. Between 40 and 45 months of service

c. Within ±2 months of the mean life