Question 1166941
z=(x-mean)/sd
the first is z < -12/15 or z<-0.8 with probability of 0.2119

for the others, z is > -8/15 or probability of 0.7031

between 40 and 50 days, 0.1613
this is z between -1.33 and -0.667
also on calculator 2nd VARS 2normalcdf (40,50,60,15) ENTER

D is 0.4772 probability (between z=-2 and z=0)