Question 1102984
Assuming normal distribution.
a. is a z between -1 and 1, since z=(x-mean)/sd
That is probability of 0.6827.
b.  between 70 and 100 is between z of -2, and 1, which is 0.8186
c.  Between 30 and 60 is a z of -6 and -3, which is probability of 0.0013
d.  Greater than 100 is a z>+1, which is 0.1587.