Question 241888
I see a lot of these, and most of them have been answered incorrectly here.

Everyone has a good start. We set up our system of equations.

Let x = the total amount of her medical bills, keep in mind she is only paying 25% AFTER her initial payment.
Plan A
A(x)= 200+.25(x-200)
Plan B
B(x)= 240+.20(x-240)

Simplify both
A(x)= 200+.25x-50 which is A(x)= 150+.25x
B(x)= 240+.2x-48 which is B(x)= 192+.2x

Now we set them up in an inequality, to show that plan B costs less than plan A
192+.2x<150+.25x
Solve
.05x>42
x>840

So she will not save money until she has a bill of $840 or more. Which is a whole $40 off from calculating as paying 25% of the whole amount.