Let

x = Rosa's present age, x>=0

y = Pilar's present age, y>= 0

x + 4 = Rosa's age in 4 years

y - 3 = Pilar's age 3 years ago

Rosa is twice as old as Pilar means:

x = 2y

In 4 years, Rosa's age will be 2 years less than Pilar's age 3 years ago means:

x + 4 = (y - 3) - 2

x + 4 = y - 5

y - x = 9

We have the following system of equations:

x = 2y

y - x = 9

........

click here to see the system of equations solved for x and y

........

x = - 18

y = - 9

The solutions are negative numbers and since we assumed that the age can only be positive, this math problem has no solution.