Equivalent weight of metal in first compound is 18.6. Equivalent weight of metal in second compound is28. The ratio of its equivalent weight in both the compounds is 18.6:28. It gives us information about valency of metal. If that is approximately equal to 0.5:1.Then the valency of metal is expected to be 2. so atomic weight of metal is equal to equivalent weight ×valency. then atomic weight =18.6×2=37.2