Question 1182086
mean = 30 lbs per month
standard deviation = 5 lbs

A random selection will give 

a. 25-35 lbs per month
z1 = (25-30)/5 = -1
z2 = (35-30)/5 = +1
P(z1<=x<=z2) 
= P(x<z2) - P(x<z1)
= 0.8413 - 0.1587
= 0.6827
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b. more than 40 lbs per month
z2 = (40-30)/5 = 2
P(x>=z2)
= 1-P(x<=z2)
= 1-0.9772
= 0.02275
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