Answer:
50 years old
Explanation:
Let's say that Mikhail's age is x.
If so, Gabrielle's age would be 13 years older, therefore x + 13
We know that the sum of their ages is 113, so we can form this equation:
x + x + 13 = 113
Solving this equation, we get:
x + x = 100
2x = 100
x = 50
50 is Mikhail's age, so Gabrielle's age is 63