Question 1166146
ln 10000=9.21
so want z<(9.21-10.35)/sqrt 2.5
z<-1.14/1.58
z< -0.72
that has probability of 0.2358

the first one z=(325-370)/30 or -45/30 or -1.5
that probability is 0.0668--for some reason I had the wrong number earlier. 
unrounded, multiply that by 20000 to get 1336.14 or 1336 batteries.