Let Gabrielle's age be = x years
Let Mikhail's age be = y years
As given, Gabrielle's age is two times Mikhail's age
[tex]x=2y[/tex]
The sum of their ages is 27
[tex]x+y=27[/tex]
Putting x=2y, we have,
[tex]2y+y=27[/tex]
[tex]3y=27[/tex]
y=9
As x+y=27, x=18
Hence, Gabrielle's age is 18 years
Mikhail's age is 9 years.