Answer:
1200 miles
Explanation:
You want to know how far you can drive in a week on a budget of 300 in a rental car that costs 120 per week and 0.15 per mile.
Solution
After you pay the 120 weekly charge from your budget of 300, you have ...
300 -120 = 180
left to pay the mileage charges.
If each mile costs 0.15, then you can afford to pay for ...
180/(0.15/mi) = 1200 mi
You can travel 1200 miles in a week for 300.
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Additional comment
If you like, you can write an equation for the cost (c) as a function of the miles driven (m):
c = 120 +0.15m
Equating that to your budget of 300, you can solve for m:
300 = 120 +0.15m
180 = 0.15m . . . . . . . . . . subtract 120
180/0.15 = 1200 = m . . . . . divide by 0.15
This solution should look a lot like the one described above.