This is a system of equations.
Let L represent Lucia, and B represent Ben
The first equation is:
L + B = 150
The second one says that for every dollar ben saved, Lucia saved twice as much. So:
L = 2B
Now, solve the system
2B + B = 150
3B = 150
B = 50
L = 2(50)
L = 100
This means that Ben saved $50, and Lucia saved $100
