An element forms two oxides containing 50% and 40% of the element by mass. Prove that the results are in agreement with the law of multiple proportions.

Explanation

To prove that the results are in agreement with the law of multiple proportions, we will follow these steps:

### Step 1: Understand the Composition of the Oxides
We have two oxides of an element:
- **Oxide 1**: Contains 50% of the element by mass.
- **Oxide 2**: Contains 40% of the element by mass.

### Step 2: Calculate the Mass of Oxygen in Each Oxide
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