Question 1028823
Probability of selling to none of the three.
{{{P(NNN)=0.8(0.8)(0.8)=0.512}}}
So the complement is selling to at least one.
{{{P=1-P(NNN)}}}
{{{P=1-0.512}}}
{{{P=0.488}}}
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It can happen three ways 
P(NNY)
P(NYN)
P(YNN)
All three probabilities are identical,
{{{P=0.8(0.8)(0.2)=0.128}}}
So for three of them,
{{{P(1Y)=0.384}}}