We need to represent the two options she has:
Option A = 500 + 65 * x
(being "x" the number of times she visits the doctor)
Option B = 300 + 95 * x
this last one is cheaper for the year, but costs more per visit.
We need to find how many visits will make Option A a better deal.
So we start by creating an inequality (we want option A to be a better deal, so to make her spend LESS than option B, and see what number of visits (x) will that correspond to.
So we want: Option A < Option B (option A less than option B)
now we write in math terms:
500 + 65 x < 300 + 95 x
and solve for "x":
subtract 65 x from both sides:
500 < 300 + 95 x - 65 x
500 < 300 + 30 x
subtract 300 from both sides:
500 - 300 < 30 x
200 < 30 x
divide both sides by 30 to isolate "x" (notice that since 30 is a POSITIVE number, the inequality doesn't change direction):
200 / 30 < x
6.666 ... < x
therefore x has to be larger than 6.666...
Therefore, when the number of visits to the doctor reaches "7" she will be already better off with Option A
Answer: Number of visitis must be 7 or more (at least 7)