Percentage spent = \(\frac{\text{Amount spent}}{\text{Original amount}} \times 100\%\).<br><br>
• Amount spent = $6<br>
• Original amount = $40<br>
• Percentage spent = \(\frac{6}{40} \times 100\%\)<br>
• = \(\frac{3}{20} \times 100\% = 15\%\)<br><br>
Mdm Hwan spent 15% of her money.<br><br>
Final Answer: 15%