According to Health Affairs Oct. 28, 2004, the median time a patient waits to see a doctor

Question:

According to Health Affairs Oct. 28, 2004, the median time a patient waits to see a doctor in a typical U.S. emergency room is 30 minutes. On a day when 150 patients visit the emergency room, what is the approximate probability that
a. More than half will wait more than 30 minutes?
b. More than 85 will wait more than 30 minutes?
c. More than 60, but fewer than 90, will wait more than 30 minutes?