Yellow-gold is an alloy that is 75.00% gold,16.00% silver and 9.00% copper (by mass). calculate the cost of the gold in a cube of the alloy 1.00 ft on a side.
Use a weighted average of the densities of the elements chemistry.bd. psu.edu/jircitano/density.html for the density of the cube.
The current price of gold (per troy ounce) and unit conversions can be found in links at the bottom of the density page.