let

m = the age of the mother

d = the age of the daughter

mother is 11 years older than twice her daughters age

m = 11 + 2d

if the mother is 25 years older than her daughter how old is the daughter:

m = 25 + d

by solving the system of equations:

m = 11 + 2d

m = 25 + d

we find:

d = 14 years

m = 39 years

click here to see the step by step solution of the system of equations:

the daughter is 14 years of age.