Left-handed = \( \frac{2}{7} \) of the class, so right-handed = \( 1 - \frac{2}{7} = \frac{5}{7} \).<br><br>
&bull; Ratio of left-handed to right-handed = \( \frac{2}{7} : \frac{5}{7} \).<br>
&bull; Multiply both sides by 7: 2 : 5.<br><br>
Final Answer: 2 : 5