Question 997497
Call the mass of gold x.
Since there is more copper, at a ratio of 8 to 5, the amount of copper is (8/5)x.
Added together, they have a mass of 18.2 kg.  Thus
x + (8/5)x = 18.2
(13/5)x = 18.2   ==> 13/5 = 2.6
x = 18.2 / 2.6
x = 7 kg gold