Finding valencies from a given element in 3 oxides

Homework Statement

The oxides of a certain element contain 27.28%, 42.86% and 52.94% oxygen. What is the ratio of valencies of the element in the 3 oxides?

The Attempt at a Solution

Molecular mass of the first oxide is 58.6, second oxide is 37.3 and that of the third is 30.22

Do specify if the above calculations are also right or wrong.

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So you have found the molecular masses of the oxide. Good.

Now use the fact that molecular mass of Oxygen atom is 16. What possibilities does it leave for the molecular mass of the other element?

Show some approximate calculations, and we'll proceed further!

I used the molecular mass of O as 16 to derieve the molecular masses of each element, where I have confusion is that after finding the molecular masses of the oxides, how can I find the valencies, means, how is the molecular mass related with valency?

So you have found the molecular masses of the oxide. Good.

Now use the fact that molecular mass of Oxygen atom is 16. What possibilities does it leave for the molecular mass of the other element?

Show some approximate calculations, and we'll proceed further!