Let us calculate how much Sophia got.
Ratio is 7:2 therefor Sophia got 7/9 of the reward
7/9 × 63 → 7 × 7 = 49 $
If Sophia got 49 then Ethan got 63 - 49 = 14 $
What fraction of the total reward did Ethan get? We divide Ethan's share with the total amount of the reward, so:
14/63 simplified = 2 / 9
So Ethan got 2/9 of the reward
We can leave it like that because it cannot be simplified further into a whole fraction or we can simplify further and give an approximate value.
If we simplify further, 2 /9 = 1 /4.5
4.5 rounded off is 5
So this makes 1/5
We can say Ethan got approximately 1/5 (a fifth) of the total reward.