answer: no solution
^someone verify me on that i'm not very intelligent
It the beginning, Rosa is twice as old as Pilar, meaning she's older than Pilar. In 4 years however, Rosa's age would be 2 years less than Pilars age 3 years ago, implying that Rosa is younger than Pilar. That doesn't make sense, referring to the beginning of the problem. Therefore, I found that there was no solution.