Answer
a. $0.0027$
b. $0.636$
c. $0.757$
Work Step by Step
a. None of the 3 households had cable TV
$p=(1-0.86)\times(1-0.86)\times(1-0.86)=0.0027$
b. All 3 households had cable TV
$p=(0.86)\times(0.86)\times(0.86)=0.636$
c. At least 1 of the 3 households had cable TV
One: $p=(0.86)\times(1-0.86)\times(1-0.86)=0.017$
Two: $p=(0.86)\times(0.86)\times(1-0.86)=0.104$
Three: $p=(0.86)\times(0.86)\times(0.86)=0.636$
Total $p=0.017+0.104+0.636=0.757$