What are the ages of Fred's friend's daughters?

Question

"How old are your daughters?" Fred asked a friend one day.
"The product of their ages is 36," replied his friend.
"You are not giving me enough information," protested Fred.
"The sum of their ages is the age of your oldest son."
"I still need more information."
"All right, then. I can tell you that the oldest daughter, who is at least a year older than the other two, is a very fine pianist."
"Ah! Now I know how old your daughters are."
What are the ages of Fred's friend's daughters?

Answer 1

9, 2 and 2

The only way that the product could be 36 and still leave two possibilities is when the sum equals 13. These possibilities being 9, 2 and 2 and 6, 6 and 1.

When friend said "I can tell you that the oldest daughter, who is at least a year older than the other two" this rules out the possibility of 6,6,1.

So the daughters ages are 9, 2 and 2.

Comments

Sorry to ask this. I did not find anywhere information so  you can make this statement: quote "The only way that the product could be 36 and still leave two possibilities when the sum equals 13".unquote. Where does the number "13" come from?
Where did you get that?
36 can be 1x1x36; 1x2x18; 1x6x6; 2x2x9; 2x3x6 etc...