Solution :
Let X denotes the number of the households tha have a cable TV.
Percentage of household that have a cable TV = 85 %
[tex]$X \sim \text{Binomial}(6, 0.85)$[/tex]
Here, we can see that each of the observations is independent and the number of the observations is fixed, n.
The probability of the success P is the same for each of the outcomes.
Therefore,
[tex]P(X=4)= \binom{6}{4}0.85^40.15^2[/tex]
= 0.08324