Answer

the expression  that explains the age of Georgia to the age of her aunt:

supposing that A is the age of the aunt and B is the age of Georgia

A x 1/3 - 2 = B

A/3 -2 = B

If the Aunt Mika has 27, means A = 27:

27/3 - 2 = B

9 - 2 = B

B = 7 

Georgia is 7 years old