A lump of gold is suspected to contain some -quantity of zinc. If the gold sample has a mass of 500g and found to have a density of 5*2g/cm^ 2 what mass of gold is present of density of gold and zing are 19*3g/cm 2*6g/cm^ 3 respectively?

Answer 1

Not sure what 5*2g/cm^2 is supposed to mean. I suspect you meant 5.2, since the density of gold is 19.3

So, if there are x grams of gold in the alloy, then
19.3x + 2.6(500-x) = 5.2*500

Answer 2

x/19.3+(500-x)/2.6=500/5.2
=288.9