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

One would have to know how many miles the trucker travels in a year. It appears as if that data is not provided. Once that total mileage per year is known, then divide that value by 10,000 to yield the number of oil changes in a year's time.