Question 1012288
Let's call their ages NOW, a and c.
Then we have
a + c = 25
or a = 25 - c
In five years we have
a + 5 = 2c
Now substituting we have
25-c + 5 = 2c
30 - c = 2c
30 = 3c
c = 10
Then
a = 25 - 10 = 15