Question 1098403
z=(x-mean)/sd,  mean is 30000, sd is 2000
z=(25000-30000)/2000=-2.5
(29000-30000)/2=-0.5
want z between -0.5 and -2.5, and from the calculator or table is 0.3023
for b
(-2000/2000)=-1 and (1000/2000)/2000=+0.5, and probability is 0.5328
for c
this is 2500/2000=+1.25 and 4500/2000=+2.5 and probability is 0.0317