After months of research the ethologist concludes 1) that the mean prey catching time was 30 seconds, 2) the standard deviation was 5.5 seconds and 3) that the scores he has collected are normally distributed. What is the percentage of shrews that:

a) catch a dragonfly in less than 18 seconds;

b) catch a dragonfly in between 22 and 45 seconds;

c) take longer than 45 seconds to catch a dragonfly?

d) take less than 30 seconds to catch its prey;