Answer: Paul is 18 years old and Gary is 12 years old.
Step-by-step explanation:
Let x represent the age of Paul.
Paul is six years older than Gary. This means that Gary's age would be
x - 6
The sum of their ages is 30. This means that
x + x - 6 = 30
2x - 6 = 30
Adding 6 to the left hand side and the right hand side of the equation, it becomes
2x - 6 + 6 = 30 + 6
2x = 36
Dividing the left hand side and the right hand side of the equation by 2, it becomes
2x/2 = 36/2
x = 18
Therefore, Paul is 18 years old.
Gary is 18 - 6 = 12 years old.