Question 912192
First find the probability that none are non-smokers.
{{{P=(160/440)(160/440)(160/440)}}}
{{{P=0.048084}}}
So the complement of none are non-smokers is that one must be a non-smoker and 
{{{P+P(1_NS)=1}}}
{{{P(1_NS)=1-P}}}
{{{P(1_NS)=1-0.048084}}}
{{{P(1_NS)=0.951916}}}