Answer:
Gabrielle is 69 while Mikhail is 23.
Explanation:
Let G represent Gabrielle's age and M represent Mikhail's age.
Gabrielle is three times Mikhail's age. In other words:

The sum of their ages is 92. In other words:

This is a system of equations. Solve. Substitute in G:

Thus, Mikhail is 23. Now, find Gabrielle's age:

Gabrielle is 69.