Xiaomei practiced the brush copybook. She originally planned to write 8 characters every morning and 7 characters in the evening. She finished the practice in 24 days. In fact, she wrote 20 characters every day. How many days would it take for her to practice the complete copybook?
小梅练习毛笔字帖，原计划每天早晨写8个字，晚上写7个字，24天练习完，实际上她每天写了20个字，她练习完整本字帖要多少天？
<gadget id="calculator">8 + 7</gadget>
<output>15</output>

<gadget id="calculator">24 / 20</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">15 * (6/5)</gadget>
<output>18</output>

<result>18</result>