This is the answer to a

Difficult Riddle. Don't read on unless you want to know the answer!

If you find all the possible ways to multiply 3 integers and get 36 (and their sums), you will come
up with the following list:

1 - 1 - 36 **38**
1 - 2 - 18 **21**
1 - 3 - 12 **16**
1 - 4 - 9 **14**
1 - 6 - 6 **13**
2 - 2 - 9 **13**
2 - 3 - 6 **11**
3 - 3 - 4 **10**

Since it would it would be resonable to assume that Dave could come up with the above answers, it means
that the house number thet John pointed to must have been 13 (the only non-unique value). If it was
any of the other numbers, he could have figured out the answer from the start. As soon as John mentioned
the oldest daughter, 1 - 6 - 6 was out, as in that case there is no oldest daughter. Thus the answer, 2 - 2 - 9!