Final answer:
Hilda's present age is 11 years and Mary's present age is 22 years.
Step-by-step explanation:
Let's assume Hilda's present age as x years.
According to the given information, Mary is twice as old as Hilda. So, Mary's present age will be 2x years.
In four years, Hilda's age will be x+4 and Mary's age will be 2x+4.
The sum of their ages will be 41 four years from now, so we can write the equation: (x+4) + (2x+4) = 41.
Simplifying the equation, we get: 3x + 8 = 41.
Subtracting 8 from both sides, we get: 3x = 33.
Dividing both sides by 3, we get: x = 11.
Therefore, Hilda's present age is 11 years and Mary's present age is 2(11) = 22 years.