Question 1119280
The z-score for any value=(x-mean)/sd
For value between 10 and 20, the z score is between 0 and +2
That is probability between 0.5000 and 0.9772, so the actual probability is the difference between the two or 0.4772

For the second, this is the probability of z being between -1 or  (10-20)/10 and 0.  The second has probability of 0.5000 and the first 0.1587, and the difference is 0.3413, which represents the probability being between the values of 10 and 20.