To find the percentage of games the baseball team won, you need to first determine the total number of games played. The team won 20 games and lost 10 games, so:
Total games = Wins + Losses = 20 + 10 = 30 games.
Next, to find the percentage of games won, you use the formula:
\[ \text{Percentage of Wins} = \left( \frac{\text{Wins}}{\text{Total Games}} \right) \times 100 \]
Plugging in the numbers:
\[ \text{Percentage of Wins} = \left( \frac{20}{30} \right) \times 100 \]
Calculating that gives:
\[ \frac{20}{30} = \frac{2}{3} \approx 0.6667 \]
Then multiplying by 100:
\[ 0.6667 \times 100 \approx 66.67% \]
The student mistakenly divided 20 by 10, which only calculated the ratio of wins to losses (2), rather than wins to total games. This error led to calculating an incorrect proportion of games won, since the correct approach needs the total number of games played for a proper percentage calculation.