Answer:
Jiri's age is 25.
Explanation:
Let P = Pamela's age
and J = Jiri's age. Then
(1) P = J - 12
(2) P + J = 38
Substitute (1) into (2) J - 12 + J = 38
Add 12 to each side J + J = 50
Combine like terms 2J = 50
Divide each side by 2 J = 25
Jiri's age is 25.