Second sentence is less common but can be symbolized.
s and k for Stephanie and Kate;
Now Five years ago Fifteen years from now Two years ago
Stepahnie s s-5 s+15
Kate k k-5 k+15 k-2
Five years ago Stephanie was four times as old as her daughter Kate
In 15 years, Stephanie will be five times as old as Kate 2 years ago
The described situation can be summarized with the system of equations,
.
Solve the system for k and s.