Two men, both the same age, sitting in a Railway Station waiting for their trains, struck.........What was his solution?

Question

Two men, both the same age, sitting in a Railway Station waiting for their trains, struck up a conversation. One said to the other,' I have three sons. Let's see how many clues I have to give you before you're able to figure out their ages. To make it easy, we'll deal in the whole years only. The question is, what are their ages next birthday?"
The other man agreed to give it a try. The first man continued.
One: the sum of my sons ages is 13. The second man shook his head.
Two: the product of their ages is the same as your age.
"Carry on," said the second man.
Three: my oldest son weighs 91 pounds.
Four: ?
"Stop," said the second man, " I think I've got it.'
What was his solution?

Answer 1

The second man could not answer after knowing the Sum total of 3 numbers and also their Product (his age).

This means that there exists two sets of numbers having two common = meaning 1 set of twins.

all possible combinations are;
1,1,11 = 11
2,2.9 = 36
3,3,7 = 42
4,4,5 = 40
5,5,3 =75
6,6,1=36

Even with this knowledge he could not answer because possible combination can be either
1) 2,2,9 = 36
OR
2) 6,6,1 = 36

Once the first man said "my oldest son weighs 91 pounds"
the second man could conclude that the correct combination is 2,2,9
OR say oldest Son of age 9 and then a set of twin of 2 years of age.

Answer 2

Answer:
the correct combination is 2,2,9