Hello, Ghe.
First of all, you seem to have all of your questions answered except #2, which definitely can be answered with the given information.
Problem 2:
Since we don't know how many teenagers there are, we will have to do some thinking. The product of
their ages is (2x2)x(3x3x3x3)x(5x5)x7....
First, the 7 can only be multiplied by a 2 to get a product in the teens...7x2 = 14. That must be one teen's age. Next, 5 must be multiplied by a 3 to get a product in the teens...5x3 = 15. Since there are two 5's, there must be 2 fifteen year-olds. Now we have left:
2x3x3 = 18.
Therefore, there must be:
1- 14 year-old
2 - 15 year-olds
1 - 18 year-old