Answer:
Afful is 21 and Naomi is 13.
Explanation:
Let
represent the age of Afful and
represent the age of Naomi.
The sum of their ages is 34. In other words:

In 5 years time, Afful will be two times the age of Naomi now. In other words:

Solve for the system. Substitute.

Afful is currently 21 and Noami is currently 13.