Veronica was 5 years old five years ago. Dorothy was 25 at the time, five times older than Veronica (5 x 5).
Veronica is 10 years old five years later. Dorothy is now 5 years older as well at 30 years of age. She now is also only three times older than Veronica (10 x 3).
I think she is fibbing, look at her picture, she should have said six years ago I was six times older than my little sister; and today, I am only three times older plus six.
Thinking about it, there could be a number of answers, but the number I had in mind was 42