How old is the youngest daughter in the following scenario?
The Johnsons have four daughters, none of whom are the same age. The oldest two are teenagers and the younger two are two years apart. If the product of the ages of the four girls is 15,600.

8-you can use either factor tree or reverse division to find out the prime factors: 15600 = 100 x 156 = 2 x 2 x 5 x 5 x 12 x 13 = 2 x 2 x 5 x 5 x 2 x 2 x 3 x 13 given two of them are teenager, then one of them must be 13 the other may be 2^4 = 16 or 3 x 5 = 15 if the other teenager is 16, then the left over factors = 3 x 5 x 5 (which is not possible to have a different of 2) therefore the other teenager must be 15 thus we will have 2 x 2 x 2 x 2 x 5 therefore, the two youngest = 2 x 2 x 2 and 2 x 5 the youngest = 2 x 2 x 2 = 8