Given :
P( X = 70 ) = 0.62 .
P( X = 80 ) = 0.23 .
To Find :
We need to find If a person reaches their 70th birthday, what is the probability that they will live to age 80 .
Solution :
We need to find :
[tex]P(X=70 | X=80 )[/tex]
We know ,
[tex]P(x,y ) = \dfrac{P(x)}{P(y)}[/tex]
So ,
[tex]P(X=70 | X=80 )=\dfrac{P(X=80)}{P(X=70)}\\\\=\dfrac{0.62}{0.23}=0.371[/tex]
Hence , this is the required solution .