oil changes in a year

Question

If the trucker changes the oil every 10,000 miles, and he starts the year with a fresh oil change, how many times will he change the oil in a year?

Answer 1

At least once -- "he starts the year with a fresh oil change"

Since the problem does not give any indication of the number of miles travelled during the year, you cannot determine when the second, the third, or any other oil change will occur. All that is given is that changes happen each 10,000 miles.

The independent variable is miles. The dependent variable is number of oil changes. So, you tell me the miles travelled during the year and I will tell you the number of oil changes that happen. It's that easy!