Answer: 7 years.
Step-by-step explanation:
Let N be the age of Nankya in years.
Since Matovu is twice as old as Nankya, his age in years is 2N.
In four years, the sum of their ages will be N + 2N + 4 = 26 years.
This simplifies to 3N + 4 = 26 years.
Subtracting 4 from both sides gives 3N = 22 years.
Dividing both sides by 3 gives N = 7 years.
Therefore, Nankya's age is 7 years.