Question 1169826
a. z<(90-85)/12 or 5/12. Probability z is less than that is 0.6615
b. between 80 and 90 done the same way. On the calculator do normalcdf(80,90,85,12) for 0.3231 probability 
c. that is a z=1.25 (100-85)/12. This is the 89.4th percentile.