Aaryan

There is a reason the question is put the way it is. You don't know that the younger ones are twins unless you do the long way.

slow computer... sorry

Can someone please explain #2 to me please?

TYounghb, youre right. Wolfgang, you need to specify. I've seen puzzles like this-they all say that friend #2 has 3 children.

I don't understand #2. can someone please explain?

and wolfgang, you should remove the twins part. It just makes it easier.

my mistake. it's the only number between. 1728 and 1730

It's easier if you write out possibilities. so three numbers multiplied to get 36: 1,1,36 1,2,18 1,3,12 1,4,9 1,6,6 2,2,9 2,3,6 3,3,4 I think thats everything. Let me know if there are more. Then we get their sums. 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 Now,the second friend would have guessed the ages of his children by now; since the sums (house numbers) are all different. But since he still cannot figure it out, it must be the two sets of numbers (1,6,6 and 2,2,9) that have the same sum. And finally, since he said "oldest one", the oldest cannot be twins. 1,6,6 is impossible, therefore the ages are 2,2 and 9.

It's the only whole number between 172 and 1730. Stupid, but true.