Sum of the ages of my five niece is 47, ages of any two of them have a common divisor greater than 1. How old is eldest?

Question

Two natural numbers have a sum of less than 100 and are greater than one.

John knows the product of the numbers and Jacob knows the sum of numbers.

The following conversation takes place between them:
John: ‘I am not aware of those numbers.’
Jacob: ‘I knew you wouldn’t be. I am not aware myself.’
John: ‘Now I know them!’
Jacob: ‘Now I know them, too!’

What are the two numbers?

Answer 1

15 years old

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Ages are 6, 6, 10, 10, 15
6 & 10 have divisor 2, 6 &15- divisor 3, 10 & 15- divisor 5
Eldest is 15 years old