Answer:
Approximately 40,000 hours
Explanation:
Time = distance/speed. T = 1,200,000,000/28,000, converted to: 1,200,000/28.
Rounding 28 to 30 for the estimate, divide by another ten: 120,000. Then divide by the remaining 3 from 30: 120,000/3 = 40,000.
It will take approximately 40,000 hours.