Verified answer

We consider 100 g

we have 69.8 g of Fe => 69.8 g / 55.847 = 1.25 moles

we have 30.2 g of O => 30.2g/ 16 = 1.89

We divide by the smallest number

1.25 / 1.25 = 1

1.89 / 1.25 = 1.5

We get FeO1.5

To get whole numbers we multiply by 2 and we have

Fe2O3

In the same way

Moles C = 83.7 / 12.011 = 6.97

Moles H = 16.3 / 1.00794 = 16.17

CH2.3

2.32 x3 = 6.96

We get C3H7