The average number of shares traded daily on the New York Stock Exchange during the past year was 1.9 million. If the distribution of daily trading volume is approximately normal, with a center at 1.9 million shares and a standard deviation of .25 million shares, on what percentage of the days was trading volume

a) more than 2 million shares?

b) less than 1.5 million shares?

c) between 1.45 and 1.75 million shares?

d) 25% of days will have trading volume less than _____ shares?