Fix-It Copiers advertises a mean time of 100 minutes for office calls with a standard deviation of 25 minutes. What percentage of calls are completed:
a. between 100 and 120 minutes?
b. in less than 120 minutes?
c. in less than 60 minutes?
d. between 120 and 150 minutes?
e. between 60 and 120 minutes?
f. Twenty percent of their jobs take more than how much time?