Answer:
The probability that exactly two of the four live in their own household and are income-qualified is = .0975
Step-by-step explanation:
Given -
Approximately 85% of persons age 70 to 84 live in their own household and are income-qualified for home purchases.
Probability of sucess ( p ) = 85% =.85
Probability of failure ( q ) = 1 - .85 =.15
n = 4
From combination of n events taking r sucess we use binomial distribution

where , r = 2
the probability that exactly two of the four live in their own household and are income-qualified is =

= 
= 
= .0975