Question 910099
c, price of copper.
Price of tin?___________c+1, price for tin.
The prices are as dollars per pound.


The description is a mixture of tin and copper, but think of the mixture as being MONEY.  


Account for the money!


Better, ACCOUNT for the PRICE of the mixture.

{{{highlight_green((4(c+1)+6c)/(4+6)=4.15)}}}
Notice this is a rational expression on the left, the ratio of the dollars of the mixture to the mass of the mixture.  This ratio is the price as DOLLARS per POUND.


Solve for c, which is, as I have assigned, the price for the copper.  Use it to get the price of the tin.