NBME form 1 block 4 - rids

[ArchivalUser]

A 50 YR old man who'd myocardial infarction was diagnosed wid hypercholesterolemia( a AD DS). His son has not be tested. What is the probability that his grand-daughter, through his son, will hav hypercholesterolemia?
a.Less tha 1 %
B 25%
C. 33%
D 50%
e. 10%

Pls explain

[ArchivalUser]

it is AD , father have it , mother obviously don't
so Aa&aa= Aa, Aa, aa, aa
what is the chance that his son will get A?
50 %
what is the chance that his son transfer it to his daughter?
the same 50 %
o,5 times 0,5=0,25

am I right?

[ArchivalUser]

yes ,its b....25%