Bob and mark talk about their families. bob says he has 3 kids, the product of their age is 72. he gives another clue: the sum of the ages of his children. mark points out there is still not enough information to accurately guess.
finally, bob says, my youngest child called justice .
mark can then correctly determine the ages of bobs children .
what are the ages ?

Bob says he has 3 kids, the product of their age is 72.
So the possible ages of Bob's kids can be taken from the factors of 72

72 = 2 * 2 * 2 * 3 * 3

Finally, bob says, my youngest child called justice.
So meaning, Bob has a youngest child. He didn't mention about a twin.

So the possible ages the following:
1, 2, 36 --> sum: 39
1, 4, 18 --> sum: 23
1, 8, 9 --> sum: 18

Once the sum of the ages will be revealed, then the possible ages are mentioned above.