Solution
For this case we can create the following notation:
x= Andy age
y = Lori Age
And from the conditions we have this:
x + y= 81
x= y +11
Replacing the second equation in the first one we got:
y+11+ y= 81
2y = 81-11
2y = 70
y= 35
And solving for x we got:
x = 35+11 = 46
Andy age = 46
Lori age = 35
