Question 406012
f is age of father; d is age of daughter

Now, f = 2d

Ten years ago
(f - 10) = 3(d - 10)

Replacing f with 2d and expanding
2d - 10 = 3d - 30
20 = d
f = 40

So the father is now twice the age of his daughter (40 = 2 x 20)
Ten years ago the father was three times the age of his daughter (30 = 3 x 10)
The answer is the father is now 40 years and the daughter is 20 years.