Really need this, its definitely on my test

Jul 2014
Got this question for my midterm, need to get it right. Only thing I think I know is that I should convert the number of atoms to moles using Avagadros number. Heres the problem:

A 67.2 sample of gold (196.97g/mol) and palladium (106.42g/mol) contains 2.49x10^23 atoms. What is the composition by mass of the alloy?

Thanks for your help
May 2010
Find the number of mols in the sample.Avogradros's number is 6.7x10^23
let x =g Palladium in sample 67.2-x=g gold in sample
x/106.42 +( 67.2-x) /196.97 = mols from above