Mass of silver = m g
Mass of gold = m /100g
Number of atoms of silver = Mass/ Atomic mass X NA
= m /108NA
Number of atoms of gold = m/ 100 X197
Ratio of number of atoms of gold to silver = Au : Ag
= m/ 100 X 197 X NA : m/ 108 NA
= 108 : 100×197
= 108 : 19700
= 1 : 182.41