Her expenses are a fixed expense of $4500 and a weekly expense of $200.
Let's call the unknown number of weeks w.
In w weeks, the weekly expenses will by 200w.
The total expense is
200w + 4500
In a week, when earns $550. In w weeks, she earns 550w.
Set the expenses equal to the earnings and solve for w.
550w = 200w + 4500
Subtract 200w from both sides.
350w = 4500
w = 12.86
It takes her 12.86 weeks to break even.
If she works 13 weeks, she begins to make a profit.
