Please help!

On January 1, 2010, Chessville has a population of 50,000 people. Chessville then enters a period of population growth. Its population increases 7% each year. On the same day, Checkersville has a population of 70,000 people. Checkersville dtarts to experience a population decline. Its population decreases 4% each year. During what year will the population of Chessville first exceed that of Checkersville?
I know how to do the first part but I started to get confused. Please help!

Question

Please help!

On January 1, 2010, Chessville has a population of 50,000 people. Chessville then enters a period of population growth. Its population increases 7% each year. On the same day, Checkersville has a population of 70,000 people. Checkersville dtarts to experience a population decline. Its population decreases 4% each year. During what year will the population of Chessville first exceed that of Checkersville? 
I know how to do the first part but I started to get confused. Please help!

anonymous · Answer

you must assume exponential growth for chessville and exponential decay for checkersville

anonymous · Answer

Yes, I just did not know how to write the problem.