Let's say that each time Lucia and Ben saved their money, it was together and at the same time.
Now, assume they saved a sum of $\$3$.

If Lucia and Ben saved $\$150$ over time and saved $\$3$ each time, how many times did they have to save?
Try using division.

In this case, Lucia and Ben must have saved $50$ separate times.
We also know that each of the $50$ times, Lucia saved $\$2$.
Using multiplication, can you now find how much Lucia saved on her own?

Lucia saved $\$100$. Now do you know how much Ben saved?