To find the percentage of shoes that are rejected, we can use the formula:
\[ \text{Percentage of rejected shoes} = \left( \frac{\text{Number of rejected shoes}}{\text{Total number of shoes}} \right) \times 100 \]
In this case, it is given that 3 out of every 200 pairs of shoes are defective.
So the calculation would be:
\[ \text{Percentage of rejected shoes} = \left( \frac{3}{200} \right) \times 100 = 1.5% \]
Therefore, 1.5% of the shoes are rejected.