Given:
• Plan A: 30 dollars per day and 12 cents per mile
,
• Plan B: 50 dollars per day with free unlimited mileage.
Let's find the range of miles where plan B will save you money.
Let's create equations representing both equations in slope-intercept form:
Plan A: y = 30 + 0.12x
Plan B: y = 50
Here, x represents the number of miles.
For plan B to save you money, the total cost of plan B will have to be lesser than the total cost of plan A.
Now to find where plan B will save you money set the expression in part B less than that of plan A.
We have:

Let's solve for x.
We have:

Therefore, to save money the mileage must be greater than 166.67 miles per day.
ANSWER:
166.67 miles