why same works are different paid

Supply and demand. BTW, Welcome to A2K. c.i.

thanks

thanks enough.
so supply and demand determined the defference of price of same amount of labor in different sections of industry, isn't this unfair?

Workers will in most instance think it is unfair, but the reality is nobody is holding that worker to that job by force. He is free to move to the other company if he thinks the pay and benefits are better. Likewise, a professional - say a doctor or lawyer who works for himself - can move to another area if he thinks he can earn more money. What usually happens is that moving to a higher income area also means a higher cost of living. I live in Silicon Valley in California; one of the highest cost area in the US. Doctors and lawyers probably on average earn more in our area, but housing and other cost of living items usually offset the higher income. Average home costs about $500,000 in our area. There are many parts in the US where one can buy a new home for half that amount.

yes they can, but this in not the point, the point is they could not change their professions easily, because when you have become proficient in one field, there would be big adventure to change to do other business. i mean the unfairness is not on individual person but on different economic sectors.